Thank you very much Mark for detailed info but i have more questions.
I am really curious.
Is this sql standard concept that i must do this in this crap way?
SELECT substring('ab11c' similar '[[:ALPHA:]]+#"[0-9]+#"[[:ALPHA:]]+' escape
'#') FROM RDB$DATABASE
Also strange that i must consume whole string by reg expression not only part
of it.
This can be as an option but as default it is strange for me.
Why not simply do:
SELECT substring('ab11c12bcd' similar '[0-9]+' itemNumber 1) FROM RDB$DATABASE
Will simply return „11”
SELECT substring('ab11c22bcd' similar '[0-9]+' itemNumber 2) FROM RDB$DATABASE
Will simply return 22
Now i have 2 udf like this:
REG_MATCH
REG_MATCH_COUNT
and i supposed that i can replace it with built in one, but i see that this is
really terrible.
Above udfs i can use in this way
SELECT REG_MATCH(‘ab11c22bcd’, ‘[0-9]+’, 1) FROM RDB$DATABASE
Return 11
SELECT REG_MATCH(‘ab11c22bcd’, ‘[0-9]+’, 2) FROM RDB$DATABASE
Return 22
SELECT REG_MATCH_COUNT(‘ab11c22bcd’, ‘[0-9]+’) FROM RDB$DATABASE
Return 2
I can use it in the where clause:
SELECT * FROM MY_TABLE T WHERE REG_MATCH_COUNT(T.FIELD, ‘[0-9]+’)>2
Or
SELECT * FROM MY_TABLE T WHERE REG_MATCH(T.FIELD, ‘[0-9]+’, 1)=’11’
regards,
Karol Bieniaszewski
