add more tests for ProjectSet (#10868)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: leiysky

src/query/sql/src/planner/optimizer/heuristic/prune_unused_columns.rs

@@ -208,16 +208,10 @@ impl UnusedColumnPruner {
             }
 
             RelOperator::ProjectSet(op) => {
-                let mut used = vec![];
-                // Only keep columns needed by parent plan.
+                // We can't prune SRFs because they may change the cardinality of result set,
+                // even if the result column of an SRF is not used by any following expression.
                 for s in op.srfs.iter() {
-                    if !required.contains(&s.index) {
-                        continue;
-                    }
-                    used.push(s.clone());
-                    s.scalar.used_columns().iter().for_each(|c| {
-                        required.insert(*c);
-                    })
+                    required.extend(s.scalar.used_columns().iter().copied());
                 }
 
                 Ok(SExpr::create_unary(

tests/sqllogictests/suites/mode/standalone/explain/project_set.test

@@ -0,0 +1,41 @@
+statement ok
+drop database if exists project_set
+
+statement ok
+create database project_set
+
+statement ok
+use project_set
+
+query T
+explain select number from (select unnest([1,2,3]), number from numbers(10)) t
+----
+ProjectSet
+├── estimated rows: 10.00
+├── set returning functions: unnest([1, 2, 3])
+└── TableScan
+    ├── table: default.system.numbers
+    ├── read rows: 10
+    ├── read bytes: 80
+    ├── partitions total: 1
+    ├── partitions scanned: 1
+    ├── push downs: [filters: [], limit: NONE]
+    └── estimated rows: 10.00
+
+query T
+explain select number from (select unnest([1,2,3,number]), number from numbers(10)) t
+----
+ProjectSet
+├── estimated rows: 10.00
+├── set returning functions: unnest(CAST(array(1, 2, 3, numbers.number (#0)) AS Array(UInt64 NULL)))
+└── TableScan
+    ├── table: default.system.numbers
+    ├── read rows: 10
+    ├── read bytes: 80
+    ├── partitions total: 1
+    ├── partitions scanned: 1
+    ├── push downs: [filters: [], limit: NONE]
+    └── estimated rows: 10.00
+
+statement ok
+drop database project_set