Returns the substring within string that matches the N'th occurrence of the POSIX regular expression pattern, or NULL if there is no such match; see Section 9.7.3.
Signatures & examples
regexp_substr ( string text, pattern text [, start integer [, N integer [, flags text [, subexpr integer ] ] ] ] ) → text
Returns the substring within string that matches the N'th occurrence of the POSIX regular expression pattern, or NULL if there is no such match; see Section 9.7.3.