Just note to anyone trying the REGEXP to use "LIKE IN" functionality.
IN allows you to do:
field IN (
'val1',
'val2',
'val3'
)
In REGEXP this won't work
REGEXP '
val1$|
val2$|
val3$
'
It has to be in one line like this:
REGEXP 'val1$|val2$|val3$'