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REGEXP_SUBSTR()

Description

REGEXP_SUBSTR() is used to return the substring of the string expr that matches the regular expression pattern pat.

Syntax

> REGEXP_SUBSTR(expr, pat[, pos[, occurrence[, match_type]]])

Explanations

  • expr: This is the original string in which to look for matches.

  • pat: This is a regular expression pattern, the function will look for strings that match this pattern.

  • pos: The position in expr at which to start the search. If omitted, the default is 1.

  • occurrence: Which occurrence of a match to replace. If omitted, the default is 0 (which means replace all occurrences).

  • match_type: The optional match_type argument is a string that may contain any or all the following characters specifying how to perform matching:

    • 'c': Case-sensitive matching by default.
    • 'i': Case-insensitive matching.
    • 'n': The . character matches line terminators. The default is for . matching to stop at the end of a line.
    • 'm': Multiple-line mode. Recognize line terminators within the string. The default behavior is to match line terminators only at the start and end of the string expression.
    • 'u': Unix-only line endings. Only the newline character is recognized as a line ending by the ., ^, and $ match operators.

Examples

```SQL mysql> SELECT REGEXP_SUBSTR('1a 2b 3c', '[0-9]a'); +---------------------------------+ | regexp_substr(1a 2b 3c, [0-9]a) | +---------------------------------+ | 1a | +---------------------------------+ 1 row in set (0.00 sec)

mysql> SELECT REGEXP_SUBSTR('Lend for land', '^C') Result; +--------+ | Result | +--------+ | NULL | +--------+ 1 row in set (0.00 sec) ```