index-constraints vars=(a int, b int) index=(a, b)
a IS NULL AND b = 2
----
[/NULL/2 - /NULL/2]

index-constraints vars=(a int, b int) index=(a, b)
a IS NULL AND b > 2
----
[/NULL/3 - /NULL]

index-constraints vars=(a int, b int) index=(a, b)
a = 1 AND b IS NULL
----
[/1/NULL - /1/NULL]

index-constraints vars=(a int, b int) index=(a, b)
a >= 1 AND b IS NULL
----
[/1/NULL - ]
Remaining filter: b IS NULL

index-constraints vars=(a int) index=(a)
a IS NOT DISTINCT FROM NULL
----
[/NULL - /NULL]

index-constraints vars=(a int) index=(a)
a IS NOT NULL
----
(/NULL - ]

index-constraints vars=(a int) index=(a)
a IS DISTINCT FROM NULL
----
(/NULL - ]

index-constraints vars=(a int) index=(a desc)
a IS NOT NULL
----
[ - /NULL)

index-constraints vars=(a int not null) index=(a)
a IS NULL
----

index-constraints vars=(a int not null) index=(a)
a IS NOT DISTINCT FROM NULL
----

index-constraints vars=(a int not null) index=(a)
a IS NOT NULL
----
[ - ]

index-constraints vars=(a int not null) index=(a)
a IS DISTINCT FROM NULL
----
[ - ]

index-constraints vars=(a int not null) index=(a desc)
a IS NOT NULL
----
[ - ]
