MySQL RegExp Got error 'repetition-operator operand invalid' from RegExp

Question

My regular expression is this:

((?:[a-z][a-z0-9_]*)).*?(\d+).*?((?:[a-z][a-z0-9_]*)).*?(\d+).*?([a-z])

If I give this as input to MySQL RegExp I get the repetition operator error.I know it occurs because of ?: and I replaced it with ^ and I also replace * ? with [^>]* an my replaced regular expression is this:

'((^[a-z][a-z0-9_]*)).[^>]*.(\\d+).[^>]*.((^[a-z][a-z0-9_]*)).[^>]*.(\\d+).[^>]*.([a-z])'

The above expression executes with no errors but the matching fails and returns wrong results.So I want to convert the first regular expression to a POSIX standard supported by mysql without loosing the constraints.

FYI, added explanation about the changes to convert the expression. — zx81
– zx81, Commented Jun 6, 2014 at 8:06

zx81 · Accepted Answer · 2014-06-06 08:10:31Z

6

The most important transformation needed is mimicking the lazy quantifier, which does not exist in MySQL. To do this, as you'll see in point 3 of the explanation, we will use mutually-incompatible expressions.

This should do it:

(([a-z][a-z0-9_]*))[^0-9]*([0-9]+)[^a-z]*(([a-z][a-z0-9_]*))[^0-9]*([0-9]+)[^a-z]*([a-z])

Unless you plan to use them, you can also get rid in capturing parentheses in places such as ([0-9]+) (where you had (\d+) before.)

Explanation

Replaced the (?: non-capturing groups with regular groups
Replaced \d with [0-9]
Replaced the lazy quantifiers with a negated character class that negates what is to follow, for instance [^a-z]* precedes [a-z], and [^0-9]* precedes [0-9]

edited Jun 6, 2014 at 8:10

answered Jun 6, 2014 at 8:03

zx81

42k10 gold badges93 silver badges106 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

MySQL RegExp Got error 'repetition-operator operand invalid' from RegExp

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related