-- -- Regular expression tests -- -- Don't want to have to double backslashes in regexes set standard_conforming_strings = on; -- Test simple quantified backrefs select 'bbbbb' ~ '^([bc])\1*$' as t; t --- t (1 row) select 'ccc' ~ '^([bc])\1*$' as t; t --- t (1 row) select 'xxx' ~ '^([bc])\1*$' as f; f --- f (1 row) select 'bbc' ~ '^([bc])\1*$' as f; f --- f (1 row) select 'b' ~ '^([bc])\1*$' as t; t --- t (1 row)