>Firebird 1.5 classic on Windows.
>Is there a limit to the number of OR conditions you can put in a where clause?
>It looks there is as I get unexpected end of command when there are some 2000 ors, but maybe that is due
>limitations of the control holding the SQL. I found some 150 ors is still fine.

Long before you reach this number of ORs, you ought to consider whether your design is ideal or not.

I don't know why you reach 2000 ORs, but I'd probably recommend you to add another table:

CREATE GENERATOR MyQueryIDGen;

CREATE TABLE RBS_OR(
ID INTEGER NOT NULL PRIMARY KEY,
MyQueryID INTEGER,
MyInteger INTEGER,
MyVarChar VARCHAR(255); /*Or longer if necessary*/

(It might or might not be desirable to have an index for MyQueryID)

Then, rather than using

WHERE FieldA STARTING WITH 'bd' or FieldA STARTING WITH 'bi' or ...

I'd grasp the next value from the generator (programmatically), insert all starting with values into RBS_OR and use

FROM RBS_OR R
JOIN Table1 T1 ON T1.FieldA STARTING R.MyVarChar
WHERE R.MyQueryID = <GraspedAndInsertedValue>

The above will only be required if you have simultaneous access from several users, each building their query dynamically. If the query is static or concurrent use of different queries isn't required, then things can be simplified.

HTH,
Set