Encryption and compression MySQL functions

Spanner supports the following MySQL encryption and compression functions. You need to implement the MySQL functions in your Spanner database before you can use them. For more information on installing the functions, see Install MySQL functions.

Function list

mysql.SHA2

mysql.SHA2(bytes_expression, hash_length)

Description

Calculates an SHA-2 checksum for the input BYTES.

This function supports the following arguments:

• bytes_expression: The BYTES value for which to calculate the checksum.
• hash_length: The chosen bit length of the hash. Supported values are 256 and 512.

Return data type

STRING

Differences from MySQL

The MySQL version of SHA2() also supports SHA-224 and SHA-384 hash lengths, which this function does not. Additionally, this function returns the checksum as a hexadecimal STRING, while the MySQL version returns binary data.

Limitations

This function only supports hash lengths of 256 and 512 bits. The output is always a hexadecimal string, not binary data. If you provide an unsupported hash_length, the function returns an error.

Example

The following example calculates the SHA-256 checksum for a BYTES value:

SELECT mysql.SHA2(B'GoogleCloud', 256) as sha256_checksum;

/*
+------------------------------------------------------------------+
| sha256_checksum                                                  |
+------------------------------------------------------------------+
| 2002A3F1F350598F5FAF799AD9C9936908230796712E24682016E5257A4D2000 |
+------------------------------------------------------------------+
*/