GoogleSQL for Bigtable supports string functions.
These string functions work on two different values:
STRING
and BYTES
data types. STRING
values must be well-formed UTF-8.
Functions that return position values, such as STRPOS,
encode those positions as INT64
. The value 1
refers to the first character (or byte), 2
refers to the second, and so on.
The value 0
indicates an invalid position. When working on STRING
types, the
returned positions refer to character positions.
All string comparisons are done byte-by-byte, without regard to Unicode canonical equivalence.
Function list
Name | Summary |
---|---|
ASCII
|
Gets the ASCII code for the first character or byte in a STRING
or BYTES value.
|
BYTE_LENGTH
|
Gets the number of BYTES in a STRING or
BYTES value.
|
CHAR_LENGTH
|
Gets the number of characters in a STRING value.
|
CHR
|
Converts a Unicode code point to a character. |
CODE_POINTS_TO_BYTES
|
Converts an array of extended ASCII code points to a
BYTES value.
|
CODE_POINTS_TO_STRING
|
Converts an array of extended ASCII code points to a
STRING value.
|
CONCAT
|
Concatenates one or more STRING or BYTES
values into a single result.
|
ENDS_WITH
|
Checks if a STRING or BYTES value is the suffix
of another value.
|
FORMAT
|
Formats data and produces the results as a STRING value.
|
FROM_BASE32
|
Converts a base32-encoded STRING value into a
BYTES value.
|
FROM_BASE64
|
Converts a base64-encoded STRING value into a
BYTES value.
|
FROM_HEX
|
Converts a hexadecimal-encoded STRING value into a
BYTES value.
|
INITCAP
|
Formats a STRING as proper case, which means that the first
character in each word is uppercase and all other characters are lowercase.
|
INSTR
|
Finds the position of a subvalue inside another value, optionally starting the search at a given offset or occurrence. |
LEFT
|
Gets the specified leftmost portion from a STRING or
BYTES value.
|
LENGTH
|
Gets the length of a STRING or BYTES value.
|
LOWER
|
Formats alphabetic characters in a STRING value as
lowercase.
Formats ASCII characters in a BYTES value as
lowercase.
|
LPAD
|
Prepends a STRING or BYTES value with a pattern.
|
LTRIM
|
Identical to the TRIM function, but only removes leading
characters.
|
NORMALIZE
|
Case-sensitively normalizes the characters in a STRING value.
|
NORMALIZE_AND_CASEFOLD
|
Case-insensitively normalizes the characters in a STRING value.
|
OCTET_LENGTH
|
Alias for BYTE_LENGTH .
|
REGEXP_CONTAINS
|
Checks if a value is a partial match for a regular expression. |
REGEXP_EXTRACT
|
Produces a substring that matches a regular expression. |
REGEXP_EXTRACT_ALL
|
Produces an array of all substrings that match a regular expression. |
REGEXP_INSTR
|
Finds the position of a regular expression match in a value, optionally starting the search at a given offset or occurrence. |
REGEXP_REPLACE
|
Produces a STRING value where all substrings that match a
regular expression are replaced with a specified value.
|
REPEAT
|
Produces a STRING or BYTES value that consists of
an original value, repeated.
|
REPLACE
|
Replaces all occurrences of a pattern with another pattern in a
STRING or BYTES value.
|
REVERSE
|
Reverses a STRING or BYTES value.
|
RIGHT
|
Gets the specified rightmost portion from a STRING or
BYTES value.
|
RPAD
|
Appends a STRING or BYTES value with a pattern.
|
RTRIM
|
Identical to the TRIM function, but only removes trailing
characters.
|
SAFE_CONVERT_BYTES_TO_STRING
|
Converts a BYTES value to a STRING value and
replace any invalid UTF-8 characters with the Unicode replacement character,
U+FFFD .
|
SOUNDEX
|
Gets the Soundex codes for words in a STRING value.
|
SPLIT
|
Splits a STRING or BYTES value, using a delimiter.
|
STARTS_WITH
|
Checks if a STRING or BYTES value is a
prefix of another value.
|
STRPOS
|
Finds the position of the first occurrence of a subvalue inside another value. |
SUBSTR
|
Gets a portion of a STRING or BYTES value.
|
SUBSTRING
|
Alias for SUBSTR |
TO_BASE32
|
Converts a BYTES value to a
base32-encoded STRING value.
|
TO_BASE64
|
Converts a BYTES value to a
base64-encoded STRING value.
|
TO_CODE_POINTS
|
Converts a STRING or BYTES value into an array of
extended ASCII code points.
|
TO_HEX
|
Converts a BYTES value to a
hexadecimal STRING value.
|
TO_INT64
|
Converts the big-endian bytes of a 64-bit signed integer into an
INT64 value. |
TO_VECTOR32
|
Converts the big-endian bytes of one or more 32-bit IEEE 754 floating
point numbers into an
ARRAY<FLOAT32> value. |
TO_VECTOR64
|
Converts the big-endian bytes of one or more 64-bit IEEE 754 floating
point numbers into an
ARRAY<FLOAT64> value. |
TRANSLATE
|
Within a value, replaces each source character with the corresponding target character. |
TRIM
|
Removes the specified leading and trailing Unicode code points or bytes
from a STRING or BYTES value.
|
UNICODE
|
Gets the Unicode code point for the first character in a value. |
UPPER
|
Formats alphabetic characters in a STRING value as
uppercase.
Formats ASCII characters in a BYTES value as
uppercase.
|
ASCII
ASCII(value)
Description
Returns the ASCII code for the first character or byte in value
. Returns
0
if value
is empty or the ASCII code is 0
for the first character
or byte.
Return type
INT64
Examples
SELECT ASCII('abcd') as A, ASCII('a') as B, ASCII('') as C, ASCII(NULL) as D;
/*-------+-------+-------+-------*
| A | B | C | D |
+-------+-------+-------+-------+
| 97 | 97 | 0 | NULL |
*-------+-------+-------+-------*/
BYTE_LENGTH
BYTE_LENGTH(value)
Description
Gets the number of BYTES
in a STRING
or BYTES
value,
regardless of whether the value is a STRING
or BYTES
type.
Return type
INT64
Examples
SELECT BYTE_LENGTH('абвгд') AS string_example;
/*----------------*
| string_example |
+----------------+
| 10 |
*----------------*/
SELECT BYTE_LENGTH(b'абвгд') AS bytes_example;
/*----------------*
| bytes_example |
+----------------+
| 10 |
*----------------*/
CHAR_LENGTH
CHAR_LENGTH(value)
Description
Gets the number of characters in a STRING
value.
Return type
INT64
Examples
SELECT CHAR_LENGTH('абвгд') AS char_length;
/*-------------*
| char_length |
+-------------+
| 5 |
*------------ */
CHR
CHR(value)
Description
Takes a Unicode code point and returns
the character that matches the code point. Each valid code point should fall
within the range of [0, 0xD7FF] and [0xE000, 0x10FFFF]. Returns an empty string
if the code point is 0
. If an invalid Unicode code point is specified, an
error is returned.
To work with an array of Unicode code points, see
CODE_POINTS_TO_STRING
Return type
STRING
Examples
SELECT CHR(65) AS A, CHR(255) AS B, CHR(513) AS C, CHR(1024) AS D;
/*-------+-------+-------+-------*
| A | B | C | D |
+-------+-------+-------+-------+
| A | ÿ | ȁ | Ѐ |
*-------+-------+-------+-------*/
SELECT CHR(97) AS A, CHR(0xF9B5) AS B, CHR(0) AS C, CHR(NULL) AS D;
/*-------+-------+-------+-------*
| A | B | C | D |
+-------+-------+-------+-------+
| a | 例 | | NULL |
*-------+-------+-------+-------*/
CODE_POINTS_TO_BYTES
CODE_POINTS_TO_BYTES(ascii_code_points)
Description
Takes an array of extended ASCII
code points
as ARRAY<INT64>
and returns BYTES
.
To convert from BYTES
to an array of code points, see
TO_CODE_POINTS.
Return type
BYTES
Examples
The following is a basic example using CODE_POINTS_TO_BYTES
.
SELECT CODE_POINTS_TO_BYTES([65, 98, 67, 100]) AS bytes;
-- Note that the result of CODE_POINTS_TO_BYTES is of type BYTES, displayed as a base64-encoded string.
-- In BYTES format, b'AbCd' is the result.
/*----------*
| bytes |
+----------+
| QWJDZA== |
*----------*/
The following example uses a rotate-by-13 places (ROT13) algorithm to encode a string.
CODE_POINTS_TO_STRING
CODE_POINTS_TO_STRING(unicode_code_points)
Description
Takes an array of Unicode code points
as ARRAY<INT64>
and returns a STRING
.
To convert from a string to an array of code points, see TO_CODE_POINTS.
Return type
STRING
Examples
The following are basic examples using CODE_POINTS_TO_STRING
.
SELECT CODE_POINTS_TO_STRING([65, 255, 513, 1024]) AS string;
/*--------*
| string |
+--------+
| AÿȁЀ |
*--------*/
SELECT CODE_POINTS_TO_STRING([97, 0, 0xF9B5]) AS string;
/*--------*
| string |
+--------+
| a例 |
*--------*/
SELECT CODE_POINTS_TO_STRING([65, 255, NULL, 1024]) AS string;
/*--------*
| string |
+--------+
| NULL |
*--------*/
The following example computes the frequency of letters in a set of words.
CONCAT
CONCAT(value1[, ...])
Description
Concatenates one or more values into a single result. All values must be
BYTES
or data types that can be cast to STRING
.
The function returns NULL
if any input argument is NULL
.
Return type
STRING
or BYTES
Examples
SELECT CONCAT('T.P.', ' ', 'Bar') as author;
/*---------------------*
| author |
+---------------------+
| T.P. Bar |
*---------------------*/
SELECT CONCAT('Summer', ' ', 1923) as release_date;
/*---------------------*
| release_date |
+---------------------+
| Summer 1923 |
*---------------------*/
With Employees AS
(SELECT
'John' AS first_name,
'Doe' AS last_name
UNION ALL
SELECT
'Jane' AS first_name,
'Smith' AS last_name
UNION ALL
SELECT
'Joe' AS first_name,
'Jackson' AS last_name)
SELECT
CONCAT(first_name, ' ', last_name)
AS full_name
FROM Employees;
/*---------------------*
| full_name |
+---------------------+
| John Doe |
| Jane Smith |
| Joe Jackson |
*---------------------*/
ENDS_WITH
ENDS_WITH(value, suffix)
Description
Takes two STRING
or BYTES
values. Returns TRUE
if suffix
is a suffix of value
.
This function supports specifying collation.
Return type
BOOL
Examples
SELECT ENDS_WITH('apple', 'e') as example
/*---------*
| example |
+---------+
| True |
*---------*/
FORMAT
FORMAT(format_string_expression, data_type_expression[, ...])
Description
FORMAT
formats a data type expression as a string.
format_string_expression
: Can contain zero or more format specifiers. Each format specifier is introduced by the%
symbol, and must map to one or more of the remaining arguments. In general, this is a one-to-one mapping, except when the*
specifier is present. For example,%.*i
maps to two arguments—a length argument and a signed integer argument. If the number of arguments related to the format specifiers is not the same as the number of arguments, an error occurs.data_type_expression
: The value to format as a string. This can be any GoogleSQL data type.
Return type
STRING
Examples
Description | Statement | Result |
---|---|---|
Simple integer | FORMAT('%d', 10) | 10 |
Integer with left blank padding | FORMAT('|%10d|', 11) | | 11| |
Integer with left zero padding | FORMAT('+%010d+', 12) | +0000000012+ |
Integer with commas | FORMAT("%'d", 123456789) | 123,456,789 |
STRING | FORMAT('-%s-', 'abcd efg') | -abcd efg- |
FLOAT64 | FORMAT('%f %E', 1.1, 2.2) | 1.100000 2.200000E+00 |
DATE | FORMAT('%t', date '2015-09-01') | 2015-09-01 |
TIMESTAMP | FORMAT('%t', timestamp '2015-09-01 12:34:56 America/Los_Angeles') | 2015‑09‑01 19:34:56+00 |
The FORMAT()
function does not provide fully customizable formatting for all
types and values, nor formatting that is sensitive to locale.
If custom formatting is necessary for a type, you must first format it using
type-specific format functions, such as FORMAT_DATE()
or FORMAT_TIMESTAMP()
.
For example:
SELECT FORMAT('date: %s!', FORMAT_DATE('%B %d, %Y', date '2015-01-02'));
Returns
date: January 02, 2015!
Supported format specifiers
%[flags][width][.precision]specifier
A format specifier adds formatting when casting a value to a string. It can optionally contain these sub-specifiers:
Additional information about format specifiers:
- %g and %G behavior
- %t and %T behavior
- Error conditions
- NULL argument handling
- Additional semantic rules
Format specifiers
Specifier | Description | Examples | Types |
d or i |
Decimal integer | 392 |
INT64 |
o |
Octal
Note: If an INT64 value is negative, an error is produced.
|
610 |
INT64 |
x |
Hexadecimal integer
Note: If an INT64 value is negative, an error is produced.
|
7fa |
INT64 |
X |
Hexadecimal integer (uppercase)
Note: If an INT64 value is negative, an error is produced.
|
7FA |
INT64 |
f |
Decimal notation, in [-](integer part).(fractional part) for finite values, and in lowercase for non-finite values | 392.650000 inf nan |
FLOAT32 FLOAT64 |
F |
Decimal notation, in [-](integer part).(fractional part) for finite values, and in uppercase for non-finite values | 392.650000 INF NAN |
FLOAT32 FLOAT64 |
e |
Scientific notation (mantissa/exponent), lowercase | 3.926500e+02 inf nan |
FLOAT32 FLOAT64 |
E |
Scientific notation (mantissa/exponent), uppercase | 3.926500E+02 INF NAN |
FLOAT32 FLOAT64 |
g |
Either decimal notation or scientific notation, depending on the input value's exponent and the specified precision. Lowercase. See %g and %G behavior for details. | 392.65 3.9265e+07 inf nan |
FLOAT32 FLOAT64 |
G |
Either decimal notation or scientific notation, depending on the input value's exponent and the specified precision. Uppercase. See %g and %G behavior for details. |
392.65 3.9265E+07 INF NAN |
FLOAT32 FLOAT64 |
s |
String of characters | sample |
STRING |
t |
Returns a printable string representing the value. Often looks
similar to casting the argument to STRING .
See %t and %T behavior.
|
sample 2014‑01‑01 |
Any type |
T |
Produces a string that is a valid GoogleSQL constant with a similar type to the value's type (maybe wider, or maybe string). See %t and %T behavior. |
'sample' b'bytes sample' 1234 2.3 date '2014‑01‑01' |
Any type |
% |
'%%' produces a single '%' | % | n/a |
The format specifier can optionally contain the sub-specifiers identified above in the specifier prototype.
These sub-specifiers must comply with the following specifications.
Flags
Flags | Description |
- |
Left-justify within the given field width; Right justification is the default (see width sub-specifier) |
+ |
Forces to precede the result with a plus or minus sign (+
or - ) even for positive numbers. By default, only negative numbers
are preceded with a - sign |
<space> | If no sign is going to be written, a blank space is inserted before the value |
# |
|
0 |
Left-pads the number with zeroes (0) instead of spaces when padding is specified (see width sub-specifier) |
' |
Formats integers using the appropriating grouping character. For example:
This flag is only relevant for decimal, hex, and octal values. |
Flags may be specified in any order. Duplicate flags are not an error. When flags are not relevant for some element type, they are ignored.
Width
Width | Description |
<number> | Minimum number of characters to be printed. If the value to be printed is shorter than this number, the result is padded with blank spaces. The value is not truncated even if the result is larger |
* |
The width is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted |
Precision
Precision | Description |
. <number> |
|
.* |
The precision is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted |
%g and %G behavior
The %g
and %G
format specifiers choose either the decimal notation (like
the %f
and %F
specifiers) or the scientific notation (like the %e
and %E
specifiers), depending on the input value's exponent and the specified
precision.
Let p stand for the specified precision (defaults to 6; 1 if the specified precision is less than 1). The input value is first converted to scientific notation with precision = (p - 1). If the resulting exponent part x is less than -4 or no less than p, the scientific notation with precision = (p - 1) is used; otherwise the decimal notation with precision = (p - 1 - x) is used.
Unless #
flag is present, the trailing zeros after the decimal point
are removed, and the decimal point is also removed if there is no digit after
it.
%t and %T behavior
The %t
and %T
format specifiers are defined for all types. The
width, precision, and flags act as they do
for %s
: the width is the minimum width and the STRING
will be
padded to that size, and precision is the maximum width
of content to show and the STRING
will be truncated to that size, prior to
padding to width.
The %t
specifier is always meant to be a readable form of the value.
The %T
specifier is always a valid SQL literal of a similar type, such as a
wider numeric type.
The literal will not include casts or a type name, except for the special case
of non-finite floating point values.
The STRING
is formatted as follows:
Type | %t | %T |
NULL of any type |
NULL | NULL |
INT64 |
123 | 123 |
FLOAT32, FLOAT64 |
123.0 (always with .0) 123e+10 inf -inf NaN
|
123.0 (always with .0) 123e+10 CAST("inf" AS <type>) CAST("-inf" AS <type>) CAST("nan" AS <type>) |
STRING | unquoted string value | quoted string literal |
BYTES |
unquoted escaped bytes e.g., abc\x01\x02 |
quoted bytes literal e.g., b"abc\x01\x02" |
BOOL | boolean value | boolean value |
ENUM | EnumName | "EnumName" |
DATE | 2011-02-03 | DATE "2011-02-03" |
TIMESTAMP | 2011-02-03 04:05:06+00 | TIMESTAMP "2011-02-03 04:05:06+00" |
ARRAY | [value, value, ...] where values are formatted with %t |
[value, value, ...] where values are formatted with %T |
STRUCT | (value, value, ...) where fields are formatted with %t |
(value, value, ...) where fields are formatted with %T Special cases: Zero fields: STRUCT() One field: STRUCT(value) |
Error conditions
If a format specifier is invalid, or is not compatible with the related
argument type, or the wrong number or arguments are provided, then an error is
produced. For example, the following <format_string>
expressions are invalid:
FORMAT('%s', 1)
FORMAT('%')
NULL argument handling
A NULL
format string results in a NULL
output STRING
. Any other arguments
are ignored in this case.
The function generally produces a NULL
value if a NULL
argument is present.
For example, FORMAT('%i', NULL_expression)
produces a NULL STRING
as
output.
However, there are some exceptions: if the format specifier is %t or %T
(both of which produce STRING
s that effectively match CAST and literal value
semantics), a NULL
value produces 'NULL' (without the quotes) in the result
STRING
. For example, the function:
FORMAT('00-%t-00', NULL_expression);
Returns
00-NULL-00
Additional semantic rules
FLOAT64
and
FLOAT32
values can be +/-inf
or NaN
.
When an argument has one of those values, the result of the format specifiers
%f
, %F
, %e
, %E
, %g
, %G
, and %t
are inf
, -inf
, or nan
(or the same in uppercase) as appropriate. This is consistent with how
GoogleSQL casts these values to STRING
. For %T
,
GoogleSQL returns quoted strings for
FLOAT64
values that don't have non-string literal
representations.
FROM_BASE32
FROM_BASE32(string_expr)
Description
Converts the base32-encoded input string_expr
into BYTES
format. To convert
BYTES
to a base32-encoded STRING
, use TO_BASE32.
Return type
BYTES
Example
SELECT FROM_BASE32('MFRGGZDF74======') AS byte_data;
-- Note that the result of FROM_BASE32 is of type BYTES, displayed as a base64-encoded string.
/*-----------*
| byte_data |
+-----------+
| YWJjZGX/ |
*-----------*/
FROM_BASE64
FROM_BASE64(string_expr)
Description
Converts the base64-encoded input string_expr
into
BYTES
format. To convert
BYTES
to a base64-encoded STRING
,
use [TO_BASE64][string-link-to-base64].
There are several base64 encodings in common use that vary in exactly which
alphabet of 65 ASCII characters are used to encode the 64 digits and padding.
See RFC 4648 for details. This
function expects the alphabet [A-Za-z0-9+/=]
.
Return type
BYTES
Example
SELECT FROM_BASE64('/+A=') AS byte_data;
-- Note that the result of FROM_BASE64 is of type BYTES, displayed as a base64-encoded string.
/*-----------*
| byte_data |
+-----------+
| /+A= |
*-----------*/
To work with an encoding using a different base64 alphabet, you might need to
compose FROM_BASE64
with the REPLACE
function. For instance, the
base64url
url-safe and filename-safe encoding commonly used in web programming
uses -_=
as the last characters rather than +/=
. To decode a
base64url
-encoded string, replace -
and _
with +
and /
respectively.
SELECT FROM_BASE64(REPLACE(REPLACE('_-A=', '-', '+'), '_', '/')) AS binary;
-- Note that the result of FROM_BASE64 is of type BYTES, displayed as a base64-encoded string.
/*--------*
| binary |
+--------+
| /+A= |
*--------*/
FROM_HEX
FROM_HEX(string)
Description
Converts a hexadecimal-encoded STRING
into BYTES
format. Returns an error
if the input STRING
contains characters outside the range
(0..9, A..F, a..f)
. The lettercase of the characters does not matter. If the
input STRING
has an odd number of characters, the function acts as if the
input has an additional leading 0
. To convert BYTES
to a hexadecimal-encoded
STRING
, use TO_HEX.
Return type
BYTES
Example
INITCAP
INITCAP(value[, delimiters])
Description
Takes a STRING
and returns it with the first character in each word in
uppercase and all other characters in lowercase. Non-alphabetic characters
remain the same.
delimiters
is an optional string argument that is used to override the default
set of characters used to separate words. If delimiters
is not specified, it
defaults to the following characters:
<whitespace> [ ] ( ) { } / | \ < > ! ? @ " ^ # $ & ~ _ , . : ; * % + -
If value
or delimiters
is NULL
, the function returns NULL
.
Return type
STRING
Examples
SELECT
'Hello World-everyone!' AS value,
INITCAP('Hello World-everyone!') AS initcap_value
/*-------------------------------+-------------------------------*
| value | initcap_value |
+-------------------------------+-------------------------------+
| Hello World-everyone! | Hello World-Everyone! |
*-------------------------------+-------------------------------*/
SELECT
'Apples1oranges2pears' as value,
'12' AS delimiters,
INITCAP('Apples1oranges2pears' , '12') AS initcap_value
/*----------------------+------------+----------------------*
| value | delimiters | initcap_value |
+----------------------+------------+----------------------+
| Apples1oranges2pears | 12 | Apples1Oranges2Pears |
*----------------------+------------+----------------------*/
INSTR
INSTR(value, subvalue[, position[, occurrence]])
Description
Returns the lowest 1-based position of subvalue
in value
.
value
and subvalue
must be the same type, either
STRING
or BYTES
.
If position
is specified, the search starts at this position in
value
, otherwise it starts at 1
, which is the beginning of
value
. If position
is negative, the function searches backwards
from the end of value
, with -1
indicating the last character.
position
is of type INT64
and cannot be 0
.
If occurrence
is specified, the search returns the position of a specific
instance of subvalue
in value
. If not specified, occurrence
defaults to 1
and returns the position of the first occurrence.
For occurrence
> 1
, the function includes overlapping occurrences.
occurrence
is of type INT64
and must be positive.
This function supports specifying collation.
Returns 0
if:
- No match is found.
- If
occurrence
is greater than the number of matches found. - If
position
is greater than the length ofvalue
.
Returns NULL
if:
- Any input argument is
NULL
.
Returns an error if:
position
is0
.occurrence
is0
or negative.
Return type
INT64
Examples
SELECT
'banana' AS value, 'an' AS subvalue, 1 AS position, 1 AS occurrence,
INSTR('banana', 'an', 1, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | 1 | 1 | 2 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'an' AS subvalue, 1 AS position, 2 AS occurrence,
INSTR('banana', 'an', 1, 2) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | 1 | 2 | 4 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'an' AS subvalue, 1 AS position, 3 AS occurrence,
INSTR('banana', 'an', 1, 3) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | 1 | 3 | 0 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'an' AS subvalue, 3 AS position, 1 AS occurrence,
INSTR('banana', 'an', 3, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | 3 | 1 | 4 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'an' AS subvalue, -1 AS position, 1 AS occurrence,
INSTR('banana', 'an', -1, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | -1 | 1 | 4 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'an' AS subvalue, -3 AS position, 1 AS occurrence,
INSTR('banana', 'an', -3, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | an | -3 | 1 | 4 |
*--------------+--------------+----------+------------+-------*/
SELECT
'banana' AS value, 'ann' AS subvalue, 1 AS position, 1 AS occurrence,
INSTR('banana', 'ann', 1, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| banana | ann | 1 | 1 | 0 |
*--------------+--------------+----------+------------+-------*/
SELECT
'helloooo' AS value, 'oo' AS subvalue, 1 AS position, 1 AS occurrence,
INSTR('helloooo', 'oo', 1, 1) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| helloooo | oo | 1 | 1 | 5 |
*--------------+--------------+----------+------------+-------*/
SELECT
'helloooo' AS value, 'oo' AS subvalue, 1 AS position, 2 AS occurrence,
INSTR('helloooo', 'oo', 1, 2) AS instr;
/*--------------+--------------+----------+------------+-------*
| value | subvalue | position | occurrence | instr |
+--------------+--------------+----------+------------+-------+
| helloooo | oo | 1 | 2 | 6 |
*--------------+--------------+----------+------------+-------*/
LEFT
LEFT(value, length)
Description
Returns a STRING
or BYTES
value that consists of the specified
number of leftmost characters or bytes from value
. The length
is an
INT64
that specifies the length of the returned
value. If value
is of type BYTES
, length
is the number of leftmost bytes
to return. If value
is STRING
, length
is the number of leftmost characters
to return.
If length
is 0, an empty STRING
or BYTES
value will be
returned. If length
is negative, an error will be returned. If length
exceeds the number of characters or bytes from value
, the original value
will be returned.
Return type
STRING
or BYTES
Examples
SELECT LEFT('banana', 3) AS results
/*---------*
| results |
+--------+
| ban |
*---------*/
SELECT LEFT(b'\xab\xcd\xef\xaa\xbb', 3) AS results
-- Note that the result of LEFT is of type BYTES, displayed as a base64-encoded string.
/*---------*
| results |
+---------+
| q83v |
*---------*/
LENGTH
LENGTH(value)
Description
Returns the length of the STRING
or BYTES
value. The returned
value is in characters for STRING
arguments and in bytes for the BYTES
argument.
Return type
INT64
Examples
SELECT
LENGTH('абвгд') AS string_example,
LENGTH(CAST('абвгд' AS BYTES)) AS bytes_example;
/*----------------+---------------*
| string_example | bytes_example |
+----------------+---------------+
| 5 | 10 |
*----------------+---------------*/
LOWER
LOWER(value)
Description
For STRING
arguments, returns the original string with all alphabetic
characters in lowercase. Mapping between lowercase and uppercase is done
according to the
Unicode Character Database
without taking into account language-specific mappings.
For BYTES
arguments, the argument is treated as ASCII text, with all bytes
greater than 127 left intact.
Return type
STRING
or BYTES
Examples
SELECT
LOWER('FOO BAR BAZ') AS example
FROM items;
/*-------------*
| example |
+-------------+
| foo bar baz |
*-------------*/
LPAD
LPAD(original_value, return_length[, pattern])
Description
Returns a STRING
or BYTES
value that consists of original_value
prepended
with pattern
. The return_length
is an INT64
that
specifies the length of the returned value. If original_value
is of type
BYTES
, return_length
is the number of bytes. If original_value
is
of type STRING
, return_length
is the number of characters.
The default value of pattern
is a blank space.
Both original_value
and pattern
must be the same data type.
If return_length
is less than or equal to the original_value
length, this
function returns the original_value
value, truncated to the value of
return_length
. For example, LPAD('hello world', 7);
returns 'hello w'
.
If original_value
, return_length
, or pattern
is NULL
, this function
returns NULL
.
This function returns an error if:
return_length
is negativepattern
is empty
Return type
STRING
or BYTES
Examples
SELECT FORMAT('%T', LPAD('c', 5)) AS results
/*---------*
| results |
+---------+
| " c" |
*---------*/
SELECT LPAD('b', 5, 'a') AS results
/*---------*
| results |
+---------+
| aaaab |
*---------*/
SELECT LPAD('abc', 10, 'ghd') AS results
/*------------*
| results |
+------------+
| ghdghdgabc |
*------------*/
SELECT LPAD('abc', 2, 'd') AS results
/*---------*
| results |
+---------+
| ab |
*---------*/
SELECT FORMAT('%T', LPAD(b'abc', 10, b'ghd')) AS results
/*---------------*
| results |
+---------------+
| b"ghdghdgabc" |
*---------------*/
LTRIM
LTRIM(value1[, value2])
Description
Identical to TRIM, but only removes leading characters.
Return type
STRING
or BYTES
Examples
SELECT CONCAT('#', LTRIM(' apple '), '#') AS example
/*-------------*
| example |
+-------------+
| #apple # |
*-------------*/
SELECT LTRIM('***apple***', '*') AS example
/*-----------*
| example |
+-----------+
| apple*** |
*-----------*/
SELECT LTRIM('xxxapplexxx', 'xyz') AS example
/*-----------*
| example |
+-----------+
| applexxx |
*-----------*/
NORMALIZE
NORMALIZE(value[, normalization_mode])
Description
Takes a string value and returns it as a normalized string. If you do not
provide a normalization mode, NFC
is used.
Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.
NORMALIZE
supports four optional normalization modes:
Value | Name | Description |
---|---|---|
NFC |
Normalization Form Canonical Composition | Decomposes and recomposes characters by canonical equivalence. |
NFKC |
Normalization Form Compatibility Composition | Decomposes characters by compatibility, then recomposes them by canonical equivalence. |
NFD |
Normalization Form Canonical Decomposition | Decomposes characters by canonical equivalence, and multiple combining characters are arranged in a specific order. |
NFKD |
Normalization Form Compatibility Decomposition | Decomposes characters by compatibility, and multiple combining characters are arranged in a specific order. |
Return type
STRING
Examples
The following example normalizes different language characters:
SELECT
NORMALIZE('\u00ea') as a,
NORMALIZE('\u0065\u0302') as b,
NORMALIZE('\u00ea') = NORMALIZE('\u0065\u0302') as normalized;
/*---+---+------------*
| a | b | normalized |
+---+---+------------+
| ê | ê | TRUE |
*---+---+------------*/
The following examples normalize different space characters:
SELECT NORMALIZE('Raha\u2004Mahan', NFKC) AS normalized_name
/*-----------------*
| normalized_name |
+-----------------+
| Raha Mahan |
*-----------------*/
SELECT NORMALIZE('Raha\u2005Mahan', NFKC) AS normalized_name
/*-----------------*
| normalized_name |
+-----------------+
| Raha Mahan |
*-----------------*/
SELECT NORMALIZE('Raha\u2006Mahan', NFKC) AS normalized_name
/*-----------------*
| normalized_name |
+-----------------+
| Raha Mahan |
*-----------------*/
SELECT NORMALIZE('Raha Mahan', NFKC) AS normalized_name
/*-----------------*
| normalized_name |
+-----------------+
| Raha Mahan |
*-----------------*/
NORMALIZE_AND_CASEFOLD
NORMALIZE_AND_CASEFOLD(value[, normalization_mode])
Description
Takes a string value and returns it as a normalized string. If you do not
provide a normalization mode, NFC
is used.
Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.
Case folding is used for the caseless
comparison of strings. If you need to compare strings and case should not be
considered, use NORMALIZE_AND_CASEFOLD
, otherwise use
NORMALIZE
.
NORMALIZE_AND_CASEFOLD
supports four optional normalization modes:
Value | Name | Description |
---|---|---|
NFC |
Normalization Form Canonical Composition | Decomposes and recomposes characters by canonical equivalence. |
NFKC |
Normalization Form Compatibility Composition | Decomposes characters by compatibility, then recomposes them by canonical equivalence. |
NFD |
Normalization Form Canonical Decomposition | Decomposes characters by canonical equivalence, and multiple combining characters are arranged in a specific order. |
NFKD |
Normalization Form Compatibility Decomposition | Decomposes characters by compatibility, and multiple combining characters are arranged in a specific order. |
Return type
STRING
Examples
SELECT
NORMALIZE('The red barn') = NORMALIZE('The Red Barn') AS normalized,
NORMALIZE_AND_CASEFOLD('The red barn')
= NORMALIZE_AND_CASEFOLD('The Red Barn') AS normalized_with_case_folding;
/*------------+------------------------------*
| normalized | normalized_with_case_folding |
+------------+------------------------------+
| FALSE | TRUE |
*------------+------------------------------*/
SELECT
'\u2168' AS a,
'IX' AS b,
NORMALIZE_AND_CASEFOLD('\u2168', NFD)=NORMALIZE_AND_CASEFOLD('IX', NFD) AS nfd,
NORMALIZE_AND_CASEFOLD('\u2168', NFC)=NORMALIZE_AND_CASEFOLD('IX', NFC) AS nfc,
NORMALIZE_AND_CASEFOLD('\u2168', NFKD)=NORMALIZE_AND_CASEFOLD('IX', NFKD) AS nkfd,
NORMALIZE_AND_CASEFOLD('\u2168', NFKC)=NORMALIZE_AND_CASEFOLD('IX', NFKC) AS nkfc;
/*---+----+-------+-------+------+------*
| a | b | nfd | nfc | nkfd | nkfc |
+---+----+-------+-------+------+------+
| Ⅸ | IX | false | false | true | true |
*---+----+-------+-------+------+------*/
SELECT
'\u0041\u030A' AS a,
'\u00C5' AS b,
NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFD)=NORMALIZE_AND_CASEFOLD('\u00C5', NFD) AS nfd,
NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFC)=NORMALIZE_AND_CASEFOLD('\u00C5', NFC) AS nfc,
NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFKD)=NORMALIZE_AND_CASEFOLD('\u00C5', NFKD) AS nkfd,
NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFKC)=NORMALIZE_AND_CASEFOLD('\u00C5', NFKC) AS nkfc;
/*---+----+-------+-------+------+------*
| a | b | nfd | nfc | nkfd | nkfc |
+---+----+-------+-------+------+------+
| Å | Å | true | true | true | true |
*---+----+-------+-------+------+------*/
OCTET_LENGTH
OCTET_LENGTH(value)
Alias for BYTE_LENGTH
.
REGEXP_CONTAINS
REGEXP_CONTAINS(value, regexp)
Description
Returns TRUE
if value
is a partial match for the regular expression,
regexp
.
If the regexp
argument is invalid, the function returns an error.
You can search for a full match by using ^
(beginning of text) and $
(end of
text). Due to regular expression operator precedence, it is good practice to use
parentheses around everything between ^
and $
.
Return type
BOOL
Examples
The following queries check to see if an email is valid:
SELECT
'foo@example.com' AS email,
REGEXP_CONTAINS('foo@example.com', r'@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+') AS is_valid
/*-----------------+----------*
| email | is_valid |
+-----------------+----------+
| foo@example.com | TRUE |
*-----------------+----------*/
```
```sql
SELECT
'www.example.net' AS email,
REGEXP_CONTAINS('www.example.net', r'@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+') AS is_valid
/*-----------------+----------*
| email | is_valid |
+-----------------+----------+
| www.example.net | FALSE |
*-----------------+----------*/
```
The following queries check to see if an email is valid. They
perform a full match, using `^` and `$`. Due to regular expression operator
precedence, it is good practice to use parentheses around everything between `^`
and `$`.
```sql
SELECT
'a@foo.com' AS email,
REGEXP_CONTAINS('a@foo.com', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
REGEXP_CONTAINS('a@foo.com', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;
/*----------------+---------------------+---------------------*
| email | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| a@foo.com | true | true |
*----------------+---------------------+---------------------*/
SELECT
'a@foo.computer' AS email,
REGEXP_CONTAINS('a@foo.computer', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
REGEXP_CONTAINS('a@foo.computer', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;
/*----------------+---------------------+---------------------*
| email | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| a@foo.computer | false | true |
*----------------+---------------------+---------------------*/
SELECT
'b@bar.org' AS email,
REGEXP_CONTAINS('b@bar.org', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
REGEXP_CONTAINS('b@bar.org', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;
/*----------------+---------------------+---------------------*
| email | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| b@bar.org | true | true |
*----------------+---------------------+---------------------*/
SELECT
'!b@bar.org' AS email,
REGEXP_CONTAINS('!b@bar.org', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
REGEXP_CONTAINS('!b@bar.org', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;
/*----------------+---------------------+---------------------*
| email | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| !b@bar.org | false | true |
*----------------+---------------------+---------------------*/
SELECT
'c@buz.net' AS email,
REGEXP_CONTAINS('c@buz.net', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
REGEXP_CONTAINS('c@buz.net', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;
/*----------------+---------------------+---------------------*
| email | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| c@buz.net | false | false |
*----------------+---------------------+---------------------*/
REGEXP_EXTRACT
REGEXP_EXTRACT(value, regexp)
Description
Returns the first substring in value
that matches the
re2 regular expression,
regexp
. Returns NULL
if there is no match.
If the regular expression contains a capturing group ((...)
), and there is a
match for that capturing group, that match is returned. If there
are multiple matches for a capturing group, the first match is returned.
Returns an error if:
- The regular expression is invalid
- The regular expression has more than one capturing group
Return type
STRING
or BYTES
Examples
SELECT REGEXP_EXTRACT('foo@example.com', r'^[a-zA-Z0-9_.+-]+') AS user_name
/*-----------*
| user_name |
+-----------+
| foo |
*-----------*/
SELECT REGEXP_EXTRACT('foo@example.com', r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.([a-zA-Z0-9-.]+$)')
/*------------------*
| top_level_domain |
+------------------+
| com |
*------------------*/
SELECT
REGEXP_EXTRACT('ab', '.b') AS result_a,
REGEXP_EXTRACT('ab', '(.)b') AS result_b,
REGEXP_EXTRACT('xyztb', '(.)+b') AS result_c,
REGEXP_EXTRACT('ab', '(z)?b') AS result_d
/*-------------------------------------------*
| result_a | result_b | result_c | result_d |
+-------------------------------------------+
| ab | a | t | NULL |
*-------------------------------------------*/
REGEXP_EXTRACT_ALL
REGEXP_EXTRACT_ALL(value, regexp)
Description
Returns an array of all substrings of value
that match the
re2 regular expression, regexp
. Returns an empty array
if there is no match.
If the regular expression contains a capturing group ((...)
), and there is a
match for that capturing group, that match is added to the results.
The REGEXP_EXTRACT_ALL
function only returns non-overlapping matches. For
example, using this function to extract ana
from banana
returns only one
substring, not two.
Returns an error if:
- The regular expression is invalid
- The regular expression has more than one capturing group
Return type
ARRAY<STRING>
or ARRAY<BYTES>
Examples
SELECT REGEXP_EXTRACT_ALL('Try `func(x)` or `func(y)`', '`(.+?)`') AS example
/*--------------------*
| example |
+--------------------+
| [func(x), func(y)] |
*--------------------*/
REGEXP_INSTR
REGEXP_INSTR(source_value, regexp [, position[, occurrence, [occurrence_position]]])
Description
Returns the lowest 1-based position of a regular expression, regexp
, in
source_value
. source_value
and regexp
must be the same type, either
STRING
or BYTES
.
If position
is specified, the search starts at this position in
source_value
, otherwise it starts at 1
, which is the beginning of
source_value
. position
is of type INT64
and must be positive.
If occurrence
is specified, the search returns the position of a specific
instance of regexp
in source_value
. If not specified, occurrence
defaults
to 1
and returns the position of the first occurrence. For occurrence
> 1,
the function searches for the next, non-overlapping occurrence.
occurrence
is of type INT64
and must be positive.
You can optionally use occurrence_position
to specify where a position
in relation to an occurrence
starts. Your choices are:
0
: Returns the start position ofoccurrence
.1
: Returns the end position ofoccurrence
+1
. If the end of the occurrence is at the end ofsource_value
,LENGTH(source_value) + 1
is returned.
Returns 0
if:
- No match is found.
- If
occurrence
is greater than the number of matches found. - If
position
is greater than the length ofsource_value
. - The regular expression is empty.
Returns NULL
if:
position
isNULL
.occurrence
isNULL
.
Returns an error if:
position
is0
or negative.occurrence
is0
or negative.occurrence_position
is neither0
nor1
.- The regular expression is invalid.
- The regular expression has more than one capturing group.
Return type
INT64
Examples
SELECT
REGEXP_INSTR('ab@cd-ef', '@[^-]*') AS instr_a,
REGEXP_INSTR('ab@d-ef', '@[^-]*') AS instr_b,
REGEXP_INSTR('abc@cd-ef', '@[^-]*') AS instr_c,
REGEXP_INSTR('abc-ef', '@[^-]*') AS instr_d,
/*---------------------------------------*
| instr_a | instr_b | instr_c | instr_d |
+---------------------------------------+
| 3 | 3 | 4 | 0 |
*---------------------------------------*/
SELECT
REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 1) AS instr_a,
REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 2) AS instr_b,
REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 3) AS instr_c,
REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 4) AS instr_d,
/*---------------------------------------*
| instr_a | instr_b | instr_c | instr_d |
+---------------------------------------+
| 2 | 2 | 10 | 10 |
*---------------------------------------*/
SELECT
REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 1) AS instr_a,
REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 2) AS instr_b,
REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 3) AS instr_c
/*-----------------------------*
| instr_a | instr_b | instr_c |
+-----------------------------+
| 2 | 10 | 18 |
*-----------------------------*/
SELECT
REGEXP_INSTR('a@cd-ef', '@[^-]*', 1, 1, 0) AS instr_a,
REGEXP_INSTR('a@cd-ef', '@[^-]*', 1, 1, 1) AS instr_b
/*-------------------*
| instr_a | instr_b |
+-------------------+
| 2 | 5 |
*-------------------*/
REGEXP_REPLACE
REGEXP_REPLACE(value, regexp, replacement)
Description
Returns a STRING
where all substrings of value
that
match regular expression regexp
are replaced with replacement
.
You can use backslashed-escaped digits (\1 to \9) within the replacement
argument to insert text matching the corresponding parenthesized group in the
regexp
pattern. Use \0 to refer to the entire matching text.
To add a backslash in your regular expression, you must first escape it. For
example, SELECT REGEXP_REPLACE('abc', 'b(.)', 'X\\1');
returns aXc
. You can
also use raw strings to remove one layer of
escaping, for example SELECT REGEXP_REPLACE('abc', 'b(.)', r'X\1');
.
The REGEXP_REPLACE
function only replaces non-overlapping matches. For
example, replacing ana
within banana
results in only one replacement, not
two.
If the regexp
argument is not a valid regular expression, this function
returns an error.
Return type
STRING
or BYTES
Examples
SELECT REGEXP_REPLACE('# Heading', r'^# ([a-zA-Z0-9\s]+$)', '<h1>\\1</h1>') AS html
/*--------------------------*
| html |
+--------------------------+
| <h1>Heading</h1> |
*--------------------------*/
REPEAT
REPEAT(original_value, repetitions)
Description
Returns a STRING
or BYTES
value that consists of original_value
, repeated.
The repetitions
parameter specifies the number of times to repeat
original_value
. Returns NULL
if either original_value
or repetitions
are NULL
.
This function returns an error if the repetitions
value is negative.
Return type
STRING
or BYTES
Examples
SELECT REPEAT('abc', 3) AS results
/*-----------*
| results |
|-----------|
| abcabcabc |
*-----------*/
SELECT REPEAT('abc', NULL) AS results
/*---------*
| results |
|---------|
| NULL |
*---------*/
SELECT REPEAT(NULL, 3) AS results
/*---------*
| results |
|---------|
| NULL |
*---------*/
REPLACE
REPLACE(original_value, from_pattern, to_pattern)
Description
Replaces all occurrences of from_pattern
with to_pattern
in
original_value
. If from_pattern
is empty, no replacement is made.
This function supports specifying collation.
Return type
STRING
or BYTES
Examples
REVERSE
REVERSE(value)
Description
Returns the reverse of the input STRING
or BYTES
.
Return type
STRING
or BYTES
Examples
SELECT REVERSE('abc') AS results
/*---------*
| results |
+---------+
| cba |
*---------*/
SELECT FORMAT('%T', REVERSE(b'1a3')) AS results
/*---------*
| results |
+---------+
| b"3a1" |
*---------*/
RIGHT
RIGHT(value, length)
Description
Returns a STRING
or BYTES
value that consists of the specified
number of rightmost characters or bytes from value
. The length
is an
INT64
that specifies the length of the returned
value. If value
is BYTES
, length
is the number of rightmost bytes to
return. If value
is STRING
, length
is the number of rightmost characters
to return.
If length
is 0, an empty STRING
or BYTES
value will be
returned. If length
is negative, an error will be returned. If length
exceeds the number of characters or bytes from value
, the original value
will be returned.
Return type
STRING
or BYTES
Examples
SELECT 'apple' AS example, RIGHT('apple', 3) AS right_example
/*---------+---------------*
| example | right_example |
+---------+---------------+
| apple | ple |
*---------+---------------*/
SELECT b'apple' AS example, RIGHT(b'apple', 3) AS right_example
-- Note that the result of RIGHT is of type BYTES, displayed as a base64-encoded string.
/*----------+---------------*
| example | right_example |
+----------+---------------+
| YXBwbGU= | cGxl |
*----------+---------------*/
RPAD
RPAD(original_value, return_length[, pattern])
Description
Returns a STRING
or BYTES
value that consists of original_value
appended
with pattern
. The return_length
parameter is an
INT64
that specifies the length of the
returned value. If original_value
is BYTES
,
return_length
is the number of bytes. If original_value
is STRING
,
return_length
is the number of characters.
The default value of pattern
is a blank space.
Both original_value
and pattern
must be the same data type.
If return_length
is less than or equal to the original_value
length, this
function returns the original_value
value, truncated to the value of
return_length
. For example, RPAD('hello world', 7);
returns 'hello w'
.
If original_value
, return_length
, or pattern
is NULL
, this function
returns NULL
.
This function returns an error if:
return_length
is negativepattern
is empty
Return type
STRING
or BYTES
Examples
SELECT FORMAT('%T', RPAD('c', 5)) AS results
/*---------*
| results |
+---------+
| "c " |
*---------*/
SELECT RPAD('b', 5, 'a') AS results
/*---------*
| results |
+---------+
| baaaa |
*---------*/
SELECT RPAD('abc', 10, 'ghd') AS results
/*------------*
| results |
+------------+
| abcghdghdg |
*------------*/
SELECT RPAD('abc', 2, 'd') AS results
/*---------*
| results |
+---------+
| ab |
*---------*/
SELECT FORMAT('%T', RPAD(b'abc', 10, b'ghd')) AS results
/*---------------*
| results |
+---------------+
| b"abcghdghdg" |
*---------------*/
RTRIM
RTRIM(value1[, value2])
Description
Identical to TRIM, but only removes trailing characters.
Return type
STRING
or BYTES
Examples
SELECT RTRIM('***apple***', '*') AS example
/*-----------*
| example |
+-----------+
| ***apple |
*-----------*/
SELECT RTRIM('applexxz', 'xyz') AS example
/*---------*
| example |
+---------+
| apple |
*---------*/
SAFE_CONVERT_BYTES_TO_STRING
SAFE_CONVERT_BYTES_TO_STRING(value)
Description
Converts a sequence of BYTES
to a STRING
. Any invalid UTF-8 characters are
replaced with the Unicode replacement character, U+FFFD
.
Return type
STRING
Examples
The following statement returns the Unicode replacement character, �.
SELECT SAFE_CONVERT_BYTES_TO_STRING(b'\xc2') as safe_convert;
SOUNDEX
SOUNDEX(value)
Description
Returns a STRING
that represents the
Soundex code for value
.
SOUNDEX produces a phonetic representation of a string. It indexes words by sound, as pronounced in English. It is typically used to help determine whether two strings, such as the family names Levine and Lavine, or the words to and too, have similar English-language pronunciation.
The result of the SOUNDEX consists of a letter followed by 3 digits. Non-latin
characters are ignored. If the remaining string is empty after removing
non-Latin characters, an empty STRING
is returned.
Return type
STRING
Examples
SELECT 'Ashcraft' AS value, SOUNDEX('Ashcraft') AS soundex
/*----------------------+---------*
| value | soundex |
+----------------------+---------+
| Ashcraft | A261 |
*----------------------+---------*/
SPLIT
SPLIT(value[, delimiter])
Description
Splits a STRING
or BYTES
value, using a delimiter. The delimiter
argument
must be a literal character or sequence of characters. You can't split with a
regular expression.
For STRING
, the default delimiter is the comma ,
.
For BYTES
, you must specify a delimiter.
Splitting on an empty delimiter produces an array of UTF-8 characters for
STRING
values, and an array of BYTES
for BYTES
values.
Splitting an empty STRING
returns an
ARRAY
with a single empty
STRING
.
This function supports specifying collation.
Return type
ARRAY<STRING>
or ARRAY<BYTES>
Examples
STARTS_WITH
STARTS_WITH(value, prefix)
Description
Takes two STRING
or BYTES
values. Returns TRUE
if prefix
is a
prefix of value
.
This function supports specifying collation.
Return type
BOOL
Examples
SELECT STARTS_WITH('bar', 'b') AS example
/*---------*
| example |
+---------+
| True |
*---------*/
STRPOS
STRPOS(value, subvalue)
Description
Takes two STRING
or BYTES
values. Returns the 1-based position of the first
occurrence of subvalue
inside value
. Returns 0
if subvalue
is not found.
This function supports specifying collation.
Return type
INT64
Examples
SELECT STRPOS('foo@example.com', '@') AS example
/*---------*
| example |
+---------+
| 4 |
*---------*/
SUBSTR
SUBSTR(value, position[, length])
Description
Gets a portion (substring) of the supplied STRING
or BYTES
value.
The position
argument is an integer specifying the starting position of the
substring.
- If
position
is1
, the substring starts from the first character or byte. - If
position
is0
or less than-LENGTH(value)
,position
is set to1
, and the substring starts from the first character or byte. - If
position
is greater than the length ofvalue
, the function produces an empty substring. - If
position
is negative, the function counts from the end ofvalue
, with-1
indicating the last character or byte.
The length
argument specifies the maximum number of characters or bytes to
return.
- If
length
is not specified, the function produces a substring that starts at the specified position and ends at the last character or byte ofvalue
. - If
length
is0
, the function produces an empty substring. - If
length
is negative, the function produces an error. - The returned substring may be shorter than
length
, for example, whenlength
exceeds the length ofvalue
, or when the starting position of the substring pluslength
is greater than the length ofvalue
.
Return type
STRING
or BYTES
Examples
SELECT SUBSTR('apple', 2) AS example
/*---------*
| example |
+---------+
| pple |
*---------*/
SELECT SUBSTR('apple', 2, 2) AS example
/*---------*
| example |
+---------+
| pp |
*---------*/
SELECT SUBSTR('apple', -2) AS example
/*---------*
| example |
+---------+
| le |
*---------*/
SELECT SUBSTR('apple', 1, 123) AS example
/*---------*
| example |
+---------+
| apple |
*---------*/
SELECT SUBSTR('apple', 123) AS example
/*---------*
| example |
+---------+
| |
*---------*/
SELECT SUBSTR('apple', 123, 5) AS example
/*---------*
| example |
+---------+
| |
*---------*/
SUBSTRING
SUBSTRING(value, position[, length])
Alias for SUBSTR
.
TO_BASE32
TO_BASE32(bytes_expr)
Description
Converts a sequence of BYTES
into a base32-encoded STRING
. To convert a
base32-encoded STRING
into BYTES
, use FROM_BASE32.
Return type
STRING
Example
SELECT TO_BASE32(b'abcde\xFF') AS base32_string;
/*------------------*
| base32_string |
+------------------+
| MFRGGZDF74====== |
*------------------*/
TO_BASE64
TO_BASE64(bytes_expr)
Description
Converts a sequence of BYTES
into a base64-encoded STRING
. To convert a
base64-encoded STRING
into BYTES
, use FROM_BASE64.
There are several base64 encodings in common use that vary in exactly which
alphabet of 65 ASCII characters are used to encode the 64 digits and padding.
See RFC 4648 for details. This
function adds padding and uses the alphabet [A-Za-z0-9+/=]
.
Return type
STRING
Example
SELECT TO_BASE64(b'\377\340') AS base64_string;
/*---------------*
| base64_string |
+---------------+
| /+A= |
*---------------*/
To work with an encoding using a different base64 alphabet, you might need to
compose TO_BASE64
with the REPLACE
function. For instance, the
base64url
url-safe and filename-safe encoding commonly used in web programming
uses -_=
as the last characters rather than +/=
. To encode a
base64url
-encoded string, replace +
and /
with -
and _
respectively.
SELECT REPLACE(REPLACE(TO_BASE64(b'\377\340'), '+', '-'), '/', '_') as websafe_base64;
/*----------------*
| websafe_base64 |
+----------------+
| _-A= |
*----------------*/
TO_CODE_POINTS
TO_CODE_POINTS(value)
Description
Takes a STRING
or BYTES
value and returns an array of INT64
values that
represent code points or extended ASCII character values.
- If
value
is aSTRING
, each element in the returned array represents a code point. Each code point falls within the range of [0, 0xD7FF] and [0xE000, 0x10FFFF]. - If
value
isBYTES
, each element in the array is an extended ASCII character value in the range of [0, 255].
To convert from an array of code points to a STRING
or BYTES
, see
CODE_POINTS_TO_STRING or
CODE_POINTS_TO_BYTES.
Return type
ARRAY<INT64>
Examples
The following examples get the code points for each element in an array of words.
SELECT
'foo' AS word,
TO_CODE_POINTS('foo') AS code_points
/*---------+------------------------------------*
| word | code_points |
+---------+------------------------------------+
| foo | [102, 111, 111] |
*---------+------------------------------------*/
SELECT
'bar' AS word,
TO_CODE_POINTS('bar') AS code_points
/*---------+------------------------------------*
| word | code_points |
+---------+------------------------------------+
| bar | [98, 97, 114] |
*---------+------------------------------------*/
SELECT
'baz' AS word,
TO_CODE_POINTS('baz') AS code_points
/*---------+------------------------------------*
| word | code_points |
+---------+------------------------------------+
| baz | [98, 97, 122] |
*---------+------------------------------------*/
SELECT
'giraffe' AS word,
TO_CODE_POINTS('giraffe') AS code_points
/*---------+------------------------------------*
| word | code_points |
+---------+------------------------------------+
| giraffe | [103, 105, 114, 97, 102, 102, 101] |
*---------+------------------------------------*/
SELECT
'llama' AS word,
TO_CODE_POINTS('llama') AS code_points
/*---------+------------------------------------*
| word | code_points |
+---------+------------------------------------+
| llama | [108, 108, 97, 109, 97] |
*---------+------------------------------------*/
The following examples convert integer representations of BYTES
to their
corresponding ASCII character values.
SELECT
b'\x66\x6f\x6f' AS bytes_value,
TO_CODE_POINTS(b'\x66\x6f\x6f') AS bytes_value_as_integer
/*------------------+------------------------*
| bytes_value | bytes_value_as_integer |
+------------------+------------------------+
| foo | [102, 111, 111] |
*------------------+------------------------*/
SELECT
b'\x00\x01\x10\xff' AS bytes_value,
TO_CODE_POINTS(b'\x00\x01\x10\xff') AS bytes_value_as_integer
/*------------------+------------------------*
| bytes_value | bytes_value_as_integer |
+------------------+------------------------+
| \x00\x01\x10\xff | [0, 1, 16, 255] |
*------------------+------------------------*/
The following example demonstrates the difference between a BYTES
result and a
STRING
result. Notice that the character Ā
is represented as a two-byte
Unicode sequence. As a result, the BYTES
version of TO_CODE_POINTS
returns
an array with two elements, while the STRING
version returns an array with a
single element.
SELECT TO_CODE_POINTS(b'Ā') AS b_result, TO_CODE_POINTS('Ā') AS s_result;
/*------------+----------*
| b_result | s_result |
+------------+----------+
| [196, 128] | [256] |
*------------+----------*/
TO_HEX
TO_HEX(bytes)
Description
Converts a sequence of BYTES
into a hexadecimal STRING
. Converts each byte
in the STRING
as two hexadecimal characters in the range
(0..9, a..f)
. To convert a hexadecimal-encoded
STRING
to BYTES
, use FROM_HEX.
Return type
STRING
Example
SELECT
b'\x00\x01\x02\x03\xAA\xEE\xEF\xFF' AS byte_string,
TO_HEX(b'\x00\x01\x02\x03\xAA\xEE\xEF\xFF') AS hex_string
/*----------------------------------+------------------*
| byte_string | hex_string |
+----------------------------------+------------------+
| \x00\x01\x02\x03\xaa\xee\xef\xff | 00010203aaeeefff |
*----------------------------------+------------------*/
TO_INT64
TO_INT64(bytes_value)
Description
Converts the big-endian bytes of a 64-bit signed integer into an INT64
value.
Definitions
bytes_value
: The big-endian bytes to convert. The length ofbytes_value
must be 8. IfNULL
, the function returnsNULL
.
Return Data Type
INT64
Example
SELECT TO_INT64(b'\x00\x00\x00\x00\x00\x00\x00d') AS integer_value
/*---------------------*
| integer_value |
+---------------------+
| 100 |
*---------------------*/
TO_VECTOR32
TO_VECTOR32(bytes_value)
Description
Converts the big-endian bytes of one or more 32-bit IEEE 754 floating point
numbers into an ARRAY
value.
Definitions
bytes_value
: The bytes to convert, which must be the concatenation of the big-endian bytes of 32-bit IEEE 754 floating point numbers. The length ofbytes_value
must be a multiple of 8. IfNULL
, the function returnsNULL
.
Return Data Type
ARRAY<FLOAT32>
Example
SELECT TO_VECTOR32(b'\x3f\xc0\x00\x00\x42\xc8\x00\x00') AS array_val
/*---------------------*
| array_val |
+---------------------+
| [ 1.5, 100.0 ] |
*---------------------*/
TO_VECTOR64
TO_VECTOR64(bytes_value)
Description
Converts the big-endian bytes of one or more 64-bit IEEE 754 floating point
numbers into an ARRAY
value.
Definitions
bytes_value
: The bytes to convert, which must be the concatenation of the big-endian bytes of 64-bit IEEE 754 floating point numbers. The length ofbytes_value
must be a multiple of 8. IfNULL
, the function returnsNULL
.
Return Data Type
ARRAY<FLOAT64>
Example
SELECT TO_VECTOR64(b'\x40\x5e\xdc\xcc\xcc\xcc\xcc\xcd\x40\x4c\x63\xd7\x0a\x3d\x70\xa4') AS array_val
/*---------------------*
| array_val |
+---------------------+
| [ 123.45, 56.78 ] |
*---------------------*/
TRANSLATE
TRANSLATE(expression, source_characters, target_characters)
Description
In expression
, replaces each character in source_characters
with the
corresponding character in target_characters
. All inputs must be the same
type, either STRING
or BYTES
.
- Each character in
expression
is translated at most once. - A character in
expression
that is not present insource_characters
is left unchanged inexpression
. - A character in
source_characters
without a corresponding character intarget_characters
is omitted from the result. - A duplicate character in
source_characters
results in an error.
Return type
STRING
or BYTES
Examples
SELECT TRANSLATE('This is a cookie', 'sco', 'zku') AS translate
/*------------------*
| translate |
+------------------+
| Thiz iz a kuukie |
*------------------*/
TRIM
TRIM(value_to_trim[, set_of_characters_to_remove])
Description
Takes a STRING
or BYTES
value to trim.
If the value to trim is a STRING
, removes from this value all leading and
trailing Unicode code points in set_of_characters_to_remove
.
The set of code points is optional. If it is not specified, all
whitespace characters are removed from the beginning and end of the
value to trim.
If the value to trim is BYTES
, removes from this value all leading and
trailing bytes in set_of_characters_to_remove
. The set of bytes is required.
Return type
STRING
ifvalue_to_trim
is aSTRING
value.BYTES
ifvalue_to_trim
is aBYTES
value.
Examples
In the following example, all leading and trailing whitespace characters are
removed from item
because set_of_characters_to_remove
is not specified.
SELECT CONCAT('#', TRIM( ' apple '), '#') AS example
/*----------*
| example |
+----------+
| #apple# |
*----------*/
In the following example, all leading and trailing *
characters are removed
from 'apple'.
SELECT TRIM('***apple***', '*') AS example
/*---------*
| example |
+---------+
| apple |
*---------*/
In the following example, all leading and trailing x
, y
, and z
characters
are removed from 'xzxapplexxy'.
SELECT TRIM('xzxapplexxy', 'xyz') as example
/*---------*
| example |
+---------+
| apple |
*---------*/
In the following example, examine how TRIM
interprets characters as
Unicode code-points. If your trailing character set contains a combining
diacritic mark over a particular letter, TRIM
might strip the
same diacritic mark from a different letter.
SELECT
TRIM('abaW̊', 'Y̊') AS a,
TRIM('W̊aba', 'Y̊') AS b,
TRIM('abaŪ̊', 'Y̊') AS c,
TRIM('Ū̊aba', 'Y̊') AS d
/*------+------+------+------*
| a | b | c | d |
+------+------+------+------+
| abaW | W̊aba | abaŪ | Ūaba |
*------+------+------+------*/
In the following example, all leading and trailing b'n'
, b'a'
, b'\xab'
bytes are removed from item
.
SELECT b'apple', TRIM(b'apple', b'na\xab') AS example
-- Note that the result of TRIM is of type BYTES, displayed as a base64-encoded string.
/*----------------------+------------------*
| item | example |
+----------------------+------------------+
| YXBwbGU= | cHBsZQ== |
*----------------------+------------------*/
UNICODE
UNICODE(value)
Description
Returns the Unicode code point for the first character in
value
. Returns 0
if value
is empty, or if the resulting Unicode code
point is 0
.
Return type
INT64
Examples
SELECT UNICODE('âbcd') as A, UNICODE('â') as B, UNICODE('') as C, UNICODE(NULL) as D;
/*-------+-------+-------+-------*
| A | B | C | D |
+-------+-------+-------+-------+
| 226 | 226 | 0 | NULL |
*-------+-------+-------+-------*/
UPPER
UPPER(value)
Description
For STRING
arguments, returns the original string with all alphabetic
characters in uppercase. Mapping between uppercase and lowercase is done
according to the
Unicode Character Database
without taking into account language-specific mappings.
For BYTES
arguments, the argument is treated as ASCII text, with all bytes
greater than 127 left intact.
Return type
STRING
or BYTES
Examples
SELECT UPPER('foo') AS example
/*---------*
| example |
+---------+
| FOO |
*---------*/