index-constraints vars=(a int, b int) index=(a)
a > 2 AND a < 4 AND b = 2
----
[/3 - /3]
Remaining filter: b = 2

index-constraints vars=(a int, b int) index=(a)
a > 2
optional: a < 4 AND b = 2
----
[/3 - /3]

index-constraints vars=(a int, b int) index=(a desc, b desc)
optional: a >= 2 AND a <= 4 AND b IN (1, 2, 3)
----
[/4/3 - /2/1]
