[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-07-31。"],[],[],null,["# SUBSTR\n\nReturns a specific sequence of characters from the text.\n\nSample usage\n------------\n\n`SUBSTR(Campaign, 1, 6)`\n\nSyntax\n------\n\n`SUBSTR(`\u003cvar translate=\"no\"\u003eX\u003c/var\u003e`, `\u003cvar translate=\"no\"\u003estart_index\u003c/var\u003e`, `\u003cvar translate=\"no\"\u003elength\u003c/var\u003e`)`\n\n### Parameters\n\n- \u003cvar translate=\"no\"\u003eX\u003c/var\u003e - A field or expression of any type.\n- \u003cvar translate=\"no\"\u003estart_index\u003c/var\u003e - The position from the start of the string from which to begin extracting.\n- \u003cvar translate=\"no\"\u003elength\u003c/var\u003e - The number of characters to extract.\n\n### Notes\n\n- The first character of a field is at index 1.\n- To begin extracting from the end of the string, use a negative index. The last character of a string is at index -1, the second to the last is at -2, etc.\n\nExamples\n--------\n\nRelated resources\n-----------------\n\n- [Calculated fields](/looker/docs/studio/about-calculated-fields)\n- [Looker Studio function list](/looker/docs/studio/function-list)"]]
