PolarDB supports the REGEXP_COUNT, REGEXP_INSTR, and REGEXP_SUBSTR functions.
These functions are used to perform a search on a string for a specific pattern that is specified by a regular expression. These functions then return the specific information about occurrences of the pattern within the string. The pattern must be a POSIX-style regular expression.
For more information about POSIX-style regular expressions, see POSIX Regular Expressions.