Remove all non-numeric characters from a field

Question

I have a results set from a webform that includes a phone number for each set. the format of this phone number is not enforced (some are xxxxxxxxxx, some are (xxx)xxx-xxxx a

Answer 1

It's not pretty, but...

UPDATE table
SET data =
 CONCAT(
    IF (SUBSTRING(data, 01, 1) REGEXP '[0-9]', SUBSTRING(data, 01, 1), '')
,   IF (SUBSTRING(data, 02, 1) REGEXP '[0-9]', SUBSTRING(data, 02, 1), '')
,   IF (SUBSTRING(data, 03, 1) REGEXP '[0-9]', SUBSTRING(data, 03, 1), '')
,   IF (SUBSTRING(data, 04, 1) REGEXP '[0-9]', SUBSTRING(data, 04, 1), '')
,   IF (SUBSTRING(data, 05, 1) REGEXP '[0-9]', SUBSTRING(data, 05, 1), '')
,   IF (SUBSTRING(data, 06, 1) REGEXP '[0-9]', SUBSTRING(data, 06, 1), '')
,   IF (SUBSTRING(data, 07, 1) REGEXP '[0-9]', SUBSTRING(data, 07, 1), '')
,   IF (SUBSTRING(data, 08, 1) REGEXP '[0-9]', SUBSTRING(data, 08, 1), '')
,   IF (SUBSTRING(data, 09, 1) REGEXP '[0-9]', SUBSTRING(data, 09, 1), '')
,   IF (SUBSTRING(data, 10, 1) REGEXP '[0-9]', SUBSTRING(data, 10, 1), '')
,   IF (SUBSTRING(data, 11, 1) REGEXP '[0-9]', SUBSTRING(data, 11, 1), '')
,   IF (SUBSTRING(data, 12, 1) REGEXP '[0-9]', SUBSTRING(data, 12, 1), '')
,   IF (SUBSTRING(data, 13, 1) REGEXP '[0-9]', SUBSTRING(data, 13, 1), '')
,   IF (SUBSTRING(data, 14, 1) REGEXP '[0-9]', SUBSTRING(data, 14, 1), '')
,   IF (SUBSTRING(data, 15, 1) REGEXP '[0-9]', SUBSTRING(data, 15, 1), '')
,   IF (SUBSTRING(data, 16, 1) REGEXP '[0-9]', SUBSTRING(data, 16, 1), '')
)
WHERE condition

You may have to duplicate the concatenated IF function more times depending on the length of field and how much formatting was entered.

See the query in action at SQLFiddle