use SQL::Tokenizer; my $query = q{f1,f2, SUM(f3),CONCAT(f4,f5, f6), sum((f1+f2)*f3)}; my @token = SQL::Tokenizer->tokenize($query); my $paren_depth = 0; my $cache = ''; while(my $val = shift @token) { if ($token[0] eq '(') { $paren_depth++; } if ($val eq ')') { $paren_depth--; if ($paren_depth == 0) { print $cache; $cache = ''; } } if ($paren_depth) { $cache .= $val; } else { print "$val\n"; } } __PRODUCES__ f1 , f2 , SUM(f3) , CONCAT(f4,f5, f6) , sum((f1+f2)*f3)