Hi Nick!

> SELECT count(*) FROM TBLTXAPPMSGQ WHERE BASEIDENT NOT IN ( '1, 2, 3' )

This counts all records that does not contain the 7 characters string
'1, 2, 3' in the BASEIDENT field (most likely all records).

> SELECT count(*) FROM TBLTXAPPMSGQ WHERE BASEIDENT NOT IN ( :str ) into :rcount2;

Same as above.

> SELECT count(*) FROM TBLTXAPPMSGQ WHERE BASEIDENT NOT IN ( 1, 2, 3 )

Unlike the other two SELECTs, this one exclude all records that have the
numbers 1 or 2 or 3 in the BASEIDENT field.

Say your table contains the following rows:

BASEIDENT
1
2
3
1, 2, 3

If BASEIDENT was a string field, the first two selects would return 3,
the last would probably return 4 (I think there is a difference between
the character '1' and the integer 1. Firebird doesn't automagically turn
one value into three, you have to split them yourself and supply three -
not one - parameters, casting them to the correct type.

HTH,
Set