Basic RegEx in Stackoverflow

Question

Given an input like one of the following, I need to check if it matches given text, of the format 'ABCD1234':

• ABCD1### matches ABCD1943, ABCD1300, but does not match ABCD2042 or FOOB3075
• DCBA[98]### matches DCBA9012, DCBA8899 but not DCBA6211
• ####1### matches ABCD1848 and BARR1093
• (ABCD|FOOB|BARR)2### matches ABCD2999, FOOB2533, BARR2222
• ABCD1234,WXYZ9876 matches only ABCD1234, WXYZ9876
• DCBA9###,DCBA8### matches the same things as DCBA[98]### above

I'm writing this like a function that has the following structure:

create or replace function modifiedRegEx(pattern text, tester text) 
RETURNS boolean
AS $re$
DECLARE
    isMatch boolean;
BEGIN
    isMatch := TRUE;
    return isMatch;
END;
$re$ LANGUAGE 'plpgsql';

Obviously the above will return TRUE every time. I was wondering if anyone could please suggest some string functions that might be helpful in checking the above? I'm at a loss, even after reading the PostgreSQL string functions docs.

Thank you.

Answer 1

Your answer is here: http://www.postgresql.org/docs/9.0/static/functions-matching.html

This one returns true:

SELECT 'DCBA9012' similar to 'DCBA[98]___';

or:

SELECT 'DCBA9012' ~ 'DCBA[98]...';