We use Delphi 7 and edb 2.16b2.
We found a problem when using count function.
I attached the sample database for analizing the problem.

/* BAD:   result: 3 */
SELECT COUNT(*)
FROM t1
WHERE EXISTS(SELECT * FROM t2 WHERE t2.t1id = t1.id);

/* GOOD:   result: 2 */
SELECT COUNT(id)
FROM t1
WHERE EXISTS(SELECT * FROM t2 WHERE t2.t1id = t1.id);

/* GOOD:   result: 2 rows */
SELECT *
FROM t1
WHERE EXISTS(SELECT * FROM t2 WHERE t2.t1id = t1.id);

codealfa


It does look like a bug,  You should report it to ElevateSoft support to bring it to Tim's attention quicker.

In the meantime I'd suggest using an alternative like

SELECT COUNT(*)
FROM t1
WHERE id in (SELECT t1id FROM t2)

Roy Lambert