GROUP BY

Tuple filtering is applied for a GROUP BY when the following criteria are met:
Here is the most common case in which tuple filtering will be applied:
SELECT max(c2) FROM t1 GROUP BY c1
Equality predicates allow tuple filtering on the following:
SELECT c2, SUM(c3)
FROM t1
WHERE c1 = 5 GROUP BY c2

SELECT max(c4)
FROM t1
WHERE c1 = 5 AND c3 = 6 GROUP BY c2
Related concepts
DISTINCT