Hi Vlad,

Thank you, however it depends on what documentation you read :-)

I read:
https://wiki.firebirdsql.org/wiki/index.php?page=SIMILAR+TO
which states:
'4' SIMILAR TO '[:DIGIT:]' -- true

And you refer (probably) to:

http://www.firebirdsql.org/rlsnotesh/rlsnotes25.html#rnfb25-dml-regex
Which states:
'4' SIMILAR TO '[[:DIGIT:]]' -- true