sql: fix record-returning udfs when used as data source

When record-returning UDFs (both implicit and `RECORD` return types) are
used as a data source in a query, the result should be treated as a row
with separate columns instead of a tuple, which is how UDF output is
normally treated. This PR closes this gap between CRDB and Postgres.

For example:

```
CREATE FUNCTION f() RETURNS RECORD AS
$$
  SELECT 1, 2, 3;
$$ LANGUAGE SQL

SELECT f()
    f
--------
 (1,2,3)

SELECT * FROM f() as foo(a int, b int, c int);
 a | b | c
---+---+---
 1 | 2 | 3
```

The behavior is the same for implicit record return types.

Epic: CRDB-19496
Fixes: #97059

Release note: None

pkg/sql/logictest/testdata/logic_test/enums

@@ -1768,7 +1768,7 @@ $$;
 query TT
 SELECT "🙏"('😊'), "🙏"(NULL:::"Emoji 😉")
 ----
-NULL  NULL
+NULL  mixed
 
 statement ok
 CREATE DATABASE "DB➕➕";

pkg/sql/logictest/testdata/logic_test/udf_record

@@ -13,15 +13,13 @@ SELECT f_one();
 ----
 (1)
 
-# TODO(97059): The following query should require a column definition list.
-statement ok
+statement error pq: a column definition list is required for functions returning \"record\"
 SELECT * FROM f_one();
 
-# TODO(97059): The following query should produce a row, not a tuple.
-query T
+query I
 SELECT * FROM f_one() AS foo (a INT);
 ----
-(1)
+1
 
 statement ok
 CREATE FUNCTION f_const() RETURNS RECORD AS
@@ -130,3 +128,235 @@ query T
 SELECT f_table();
 ----
 (1,5)
+
+# subtest datasource
+
+statement ok
+CREATE FUNCTION f_tup() RETURNS RECORD AS
+$$
+  SELECT ROW(1, 2, 3);
+$$ LANGUAGE SQL;
+
+query T
+SELECT f_tup();
+----
+(1,2,3)
+
+statement error pq: a column definition list is required for functions returning \"record\"
+SELECT * FROM f_tup();
+
+query III colnames
+SELECT * FROM f_tup() as foo(a int, b int, c int);
+----
+a b c
+1 2 3
+
+statement ok
+CREATE FUNCTION f_col() RETURNS RECORD AS
+$$
+  SELECT 1, 2, 3;
+$$ LANGUAGE SQL;
+
+query T
+SELECT f_col();
+----
+(1,2,3)
+
+query III colnames
+SELECT * FROM f_col() as foo(a int, b int, c int);
+----
+a b c
+1 2 3
+
+statement ok
+CREATE TABLE t_imp (a INT PRIMARY KEY, b INT);
+INSERT INTO t_imp VALUES (1, 10), (2, 4), (3, 32);
+
+statement ok
+CREATE FUNCTION f_imp() RETURNS t_imp AS
+$$
+  SELECT * FROM t_imp ORDER BY a LIMIT 1;
+$$ LANGUAGE SQL;
+
+query II colnames
+SELECT * FROM f_imp();
+----
+a b
+1 10
+
+statement ok
+CREATE TYPE udt AS ENUM ('a', 'b', 'c');
+
+statement ok
+CREATE FUNCTION f_udt() RETURNS udt AS
+$$
+  SELECT 'a'::udt;
+$$ LANGUAGE SQL;
+
+query T
+SELECT * FROM f_udt();
+----
+a
+
+statement ok
+CREATE FUNCTION f_udt_record() RETURNS RECORD AS
+$$
+  SELECT 'a'::udt;
+$$ LANGUAGE SQL;
+
+query T
+SELECT * FROM f_udt() AS foo(u udt);
+----
+a
+
+query II rowsort
+SELECT * FROM f_setof() AS foo(a INT, b INT);
+----
+1 5
+2 6
+3 7
+
+statement ok
+CREATE FUNCTION f_setof_imp() RETURNS SETOF t_imp AS
+$$
+  SELECT * FROM t_imp;
+$$ LANGUAGE SQL;
+
+query II rowsort
+SELECT * FROM f_setof_imp()
+----
+1 10
+2 4
+3 32
+
+statement ok
+CREATE FUNCTION f_strict() RETURNS RECORD STRICT AS
+$$
+  SELECT 1, 2, 3;
+$$ LANGUAGE SQL;
+
+query III
+SELECT * FROM f_strict() AS foo(a INT, b INT, c INT);
+----
+1 2 3
+
+statement ok
+CREATE FUNCTION f_setof_strict() RETURNS SETOF RECORD STRICT AS
+$$
+  SELECT * FROM t_imp;
+$$ LANGUAGE SQL;
+
+query II rowsort
+SELECT * FROM f_setof_strict() AS foo(a INT, b INT);
+----
+1 10
+2 4
+3 32
+
+statement ok
+CREATE FUNCTION f_strict_arg(IN a INT, IN b INT) RETURNS RECORD STRICT AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+query II colnames
+SELECT * FROM f_strict_arg(1,2) AS foo(a INT, b INT);
+----
+a b
+1 2
+
+query II colnames
+SELECT * FROM f_strict_arg(NULL, 2) AS foo(a INT, b INT);
+----
+a    b
+NULL NULL
+
+statement ok
+CREATE FUNCTION f_strict_arg_setof(IN a INT, IN b INT) RETURNS SETOF RECORD STRICT AS
+$$
+  SELECT a, b FROM generate_series(1,3);
+$$ LANGUAGE SQL;
+
+query II colnames
+SELECT * FROM f_strict_arg_setof(1,2) AS foo(a INT, b INT);
+----
+a b
+1 2
+1 2
+1 2
+
+# Strict SETOF UDF with NULL input returns 0 rows.
+query II colnames
+SELECT * FROM f_strict_arg_setof(NULL,2) AS foo(a INT, b INT);
+----
+a b
+
+statement ok
+CREATE TABLE n (a INT PRIMARY KEY, b INT);
+INSERT INTO n VALUES (1, 5), (2, NULL);
+
+query III colnames
+WITH narg AS (SELECT b AS input FROM n WHERE a = 2) SELECT * FROM narg, f_strict_arg(narg.input, 2) AS foo(a INT, b INT);
+----
+input a    b
+NULL NULL NULL
+
+query III colnames
+WITH narg AS (SELECT b AS input FROM n WHERE a = 2) SELECT * FROM narg, f_strict_arg_SETOF(narg.input, 2) AS foo(a INT, b INT);
+----
+input a b
+
+statement ok
+CREATE FUNCTION f_arg(IN a INT8, IN b INT8) RETURNS RECORD AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+query II
+SELECT * FROM f_arg(1,2) AS foo(a INT, b INT);
+----
+1 2
+
+# Test ambiguous function signatures with records
+subtest ambiguity
+
+# setof
+statement ok
+CREATE FUNCTION f_amb_setof(a INT8, b INT8) RETURNS SETOF RECORD STRICT AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+statement ok
+CREATE FUNCTION f_amb_setof(a INT8, b STRING) RETURNS SETOF RECORD STRICT AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+# TODO(harding): In postgres, calls to f_amb_setof should succeed and return 0 rows.
+statement error pq: ambiguous call: f_amb_setof\(int, unknown\), candidates are
+SELECT f_amb_setof(1, NULL);
+
+statement error pq: ambiguous call: f_amb_setof\(int, unknown\), candidates are
+SELECT * FROM f_amb_setof(1, NULL) as foo(a int, b int);
+
+statement ok
+CREATE FUNCTION f_amb(a INT, b INT) RETURNS RECORD STRICT AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+statement ok
+CREATE FUNCTION f_amb(a INT, b STRING) RETURNS RECORD STRICT AS
+$$
+  SELECT a, b;
+$$ LANGUAGE SQL;
+
+# TODO(harding): In postgres, calls to f_amb should succeed and return NULL.
+statement error pq: ambiguous call: f_amb\(int, unknown\), candidates are
+SELECT f_amb(1, NULL);
+
+# TODO(harding): In postgres, calls to f_amb as a data source should succeed
+# and return NULL NULL.
+statement error pq: ambiguous call: f_amb\(int, unknown\), candidates are
+SELECT * FROM f_amb(1, NULL) as foo(a int, b int);

pkg/sql/logictest/testdata/logic_test/udf_setof

@@ -166,25 +166,36 @@ CREATE FUNCTION all_ab() RETURNS SETOF ab LANGUAGE SQL AS $$
   SELECT a, b FROM ab
 $$
 
-# TODO(mgartner): This should return separate columns, not a tuple. See #97059.
-query T rowsort
+query II rowsort
 SELECT * FROM all_ab()
 ----
-(1,10)
-(2,20)
-(3,30)
-(4,40)
+1 10
+2 20
+3 30
+4 40
 
 statement ok
 CREATE FUNCTION all_ab_tuple() RETURNS SETOF ab LANGUAGE SQL AS $$
   SELECT (a, b) FROM ab
 $$
 
-# TODO(mgartner): This should return separate columns, not a tuple. See #97059.
-query T rowsort
+query II rowsort
+SELECT * FROM all_ab_tuple()
+----
+1 10
+2 20
+3 30
+4 40
+
+statement ok
+CREATE FUNCTION all_ab_record() RETURNS SETOF RECORD LANGUAGE SQL AS $$
+  SELECT a, b FROM ab
+$$
+
+query II rowsort
 SELECT * FROM all_ab_tuple()
 ----
-(1,10)
-(2,20)
-(3,30)
-(4,40)
+1 10
+2 20
+3 30
+4 40

pkg/sql/opt/exec/execbuilder/scalar.go

@@ -691,6 +691,8 @@ func (b *Builder) buildExistsSubquery(
 				types.Bool,
 				false, /* enableStepping */
 				true,  /* calledOnNullInput */
+				false, /* multiColOutput */
+				false, /* generator */
 			),
 			tree.DBoolFalse,
 		}, types.Bool), nil
@@ -779,6 +781,8 @@ func (b *Builder) buildSubquery(
 			subquery.Typ,
 			false, /* enableStepping */
 			true,  /* calledOnNullInput */
+			false, /* multiColOutput */
+			false, /* generator */
 		), nil
 	}
 
@@ -831,6 +835,8 @@ func (b *Builder) buildSubquery(
 			subquery.Typ,
 			false, /* enableStepping */
 			true,  /* calledOnNullInput */
+			false, /* multiColOutput */
+			false, /* generator */
 		), nil
 	}
 
@@ -913,6 +919,8 @@ func (b *Builder) buildUDF(ctx *buildScalarCtx, scalar opt.ScalarExpr) (tree.Typ
 		udf.Typ,
 		enableStepping,
 		udf.CalledOnNullInput,
+		udf.MultiColOutput,
+		udf.Generator,
 	), nil
 }
 

pkg/sql/opt/ops/scalar.opt

@@ -1282,6 +1282,12 @@ define UDFPrivate {
     # operators. Non-scalar UDFs are always in a project-set operator, while
     # scalar UDFs can be if used as a data source (e.g. SELECT * FROM udf()).
     CalledOnNullInput bool
+
+    # MultiColOutput is true if the function may return multiple columns.
+    MultiColOutput bool
+
+    # Generator is true if the function may output a set of rows.
+    Generator bool
 }
 
 # KVOptions is a set of KVOptionItems that specify arbitrary keys and values

pkg/sql/opt/optbuilder/builder.go

@@ -137,6 +137,9 @@ type Builder struct {
 	// within.
 	insideUDF bool
 
+	// insideDataSource is true when we are processing a data source.
+	insideDataSource bool
+
 	// If set, we are collecting view dependencies in schemaDeps. This can only
 	// happen inside view/function definitions.
 	//