Returns the position within string where the N'th match of the POSIX regular expression pattern occurs, or zero if there is no such match; see Section 9.7.3.
Signatures & examples
regexp_instr ( string text, pattern text [, start integer [, N integer [, endoption integer [, flags text [, subexpr integer ] ] ] ] ] ) → integer
Returns the position within string where the N'th match of the POSIX regular expression pattern occurs, or zero if there is no such match; see Section 9.7.3.