REGEXP_SUBSTR

Returns the substring of the string expr that matches the regular expression specified by the pattern pat, NULL if there is no match. If expr or pat is NULL, the return value is NULL.

Syntax

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

Arguments

Arguments	Description
expr	The string expr that to be matched
pat	The regular expression
pos	Optional. The position in expr at which to start the search. If omitted, the default is 1.
occurrence	Optional. Which occurrence of a match to search for. If omitted, the default is 1.
match_type	Optional. A string that specifies how to perform matching. The meaning is as described for REGEXP_LIKE().

Return Type

A String data type value.

Examples

SELECT REGEXP_SUBSTR('abc def ghi', '[a-z]+');
+----------------------------------------+
| REGEXP_SUBSTR('abc def ghi', '[a-z]+') |
+----------------------------------------+
| abc                                    |
+----------------------------------------+

SELECT REGEXP_SUBSTR('abc def ghi', '[a-z]+', 1, 3);
+----------------------------------------------+
| REGEXP_SUBSTR('abc def ghi', '[a-z]+', 1, 3) |
+----------------------------------------------+
| ghi                                          |
+----------------------------------------------+

SELECT REGEXP_SUBSTR('周 周周 周周周 周周周周', '周+', 2, 3);
+------------------------------------------------------------------+
| REGEXP_SUBSTR('周 周周 周周周 周周周周', '周+', 2, 3)            |
+------------------------------------------------------------------+
| 周周周周                                                         |
+------------------------------------------------------------------+