+------------------+----------+------+-----+---------------------+-------+
| Field            | Type     | Null | Key | Default             | Extra |
+------------------+----------+------+-----+---------------------+-------+
| questionnaire_id | int(11)  | NO   | PRI | 0                   |       |
| participant_id   | int(11)  | NO   | PRI | 0                   |       |
| question_id      | int(11)  | NO   | PRI | 0                   |       |
| answer_id        | int(11)  | NO   | PRI | 0                   |       |
| date_time        | datetime | NO   | PRI | 0000-00-00 00:00:00 |       |
| freetext         | text     | NO   |     |                     |       |
+------------------+----------+------+-----+---------------------+-------+

Currently the filters are combined by generating single sql that should
return the terminal list. Here's the example of generated sql:

SELECT participant_id FROM (
   
    SELECT participant_id, count(participant_id) as rcount
    FROM participant_answer
    WHERE (
        ( question_id = 76 AND answer_id in ('20')) OR
        ( question_id = 103 AND answer_id in ('87'))
          )
    GROUP BY participant_id

) AS temporarySelectTable where rcount>=2


This should return a list of participant_id's inner select's list of
terminals where rcount>=2.

But this fails because for example, participant 36 has answered the
question 76 4 times so his rcount is actually 4 and he's making it to
the final list  anyway.

Problem here is that the inner select should read only one row, not all
4 rows.  Any ideas how to select that inner select query to return only
one answer per/answer pair ?

Addition:

The inner selection returns this:

+----------------+--------+
| participant_id | rcount |
+----------------+--------+
|              1 |      2 |
|              6 |      1 |
|             36 |      4 |
|             40 |      4 |
+----------------+--------+

Reason is that participant answer has 1 answers in question 76 and none in question 103. participants 36 and 40 have *4* answers in  question 76 and none in 103.

So should find the way to limit the inner select to only the highest date_time or just any single answer.