exec-ddl
CREATE TABLE b (k INT PRIMARY KEY, i INT, f FLOAT, s STRING NOT NULL, j JSON)
----
TABLE b
 ├── k int not null
 ├── i int
 ├── f float
 ├── s string not null
 ├── j jsonb
 └── INDEX primary
      └── k int not null

# --------------------------------------------------
# EliminateUnionAllLeft
# --------------------------------------------------

opt expect=EliminateUnionAllLeft
SELECT k FROM
  (SELECT k FROM b)
  UNION ALL
  (SELECT k FROM b WHERE k IN ())
----
project
 ├── columns: k:11(int)
 ├── scan b
 │    ├── columns: b.k:1(int!null)
 │    └── key: (1)
 └── projections
      └── variable: b.k [type=int, outer=(1)]

# --------------------------------------------------
# EliminateUnionAllRight
# --------------------------------------------------

opt expect=EliminateUnionAllRight
SELECT k FROM
  (SELECT k FROM b WHERE Null)
  UNION ALL
  (SELECT k FROM b)
----
project
 ├── columns: k:11(int)
 ├── scan b
 │    ├── columns: b.k:6(int!null)
 │    └── key: (6)
 └── projections
      └── variable: b.k [type=int, outer=(6)]

opt
SELECT k FROM
  (SELECT k FROM b WHERE False)
  UNION ALL
  (SELECT k FROM b WHERE i IN ())
----
values
 ├── columns: k:11(int)
 ├── cardinality: [0 - 0]
 ├── key: ()
 └── fd: ()-->(11)
