Hi,
I stumbled over this question on Stackoverflow
http://stackoverflow.com/questions/13564369/postgresql-using-column-data-as-pattern-for-regexp-match
And my initial reaction was, that this should be possible using regexp_matches.
So I tried:
SELECT * FROM some_table WHERE regexp_matches(somecol, 'foobar') is not null;
However that resulted in: ERROR: argument of WHERE must not return a set
Hmm, even though an array is not a set I can partly see what the problem is
(although given the really cool array implementation in PostgreSQL I was a bit surprised).
So I though, if I convert this to an integer, it should work:
SELECT * FROM some_table WHERE array_length(regexp_matches(somecol, 'foobar'), 1) > 0
but that still results in the same error.
But array_length() clearly returns an integer, so why does it still throw this error?
I'm using 9.2.1
Regards
Thomas