Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> writes: > Doug Gorley escribió: >> Trying to match some numbers, and I'm having some regexp problems. >> I've boiled it down to the following: >> >> /* (1) */ select '3.14' similar to E'^\\d+\\.\\d+$'; -- true >> /* (2) */ select '3.14' similar to E'^\\d+(\\.\\d+)$'; -- true >> /* (3) */ select '3.14' similar to E'^\\d+(\\.\\d+)*$'; -- true >> /* (4) */ select '3.14' similar to E'^\\d+(\\.\\d+)?$'; -- false >> /* (5) */ select '3.14' similar to E'^\\d+(\\.\\d+)+$'; -- true >> >> So, based on (1) and (2), the pattern '\.\d+' occurs once. So why >> does (4) return false? between (3), (4), and (5), it appears as >> though the group is matching multiple times. > I think the confusion is about what SIMILAR TO supports. ? it doesn't. > See here: > http://www.postgresql.org/docs/8.4/static/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP > You probably want to use ~ instead of SIMILAR TO. > (SIMILAR TO is a weird beast that the SQL committee came up with, > vaguely based on regular expressions.) Hmm ... actually I think *none* of those should have succeeded, because ^ and $ are not supposed to be metacharacters in SIMILAR TO. We are failing to quote them, but apparently we need to --- it looks like the regexp engine processes ^^ at the start of the pattern the same as ^, and likewise for $$ at the end. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
