Merge pull request #3325 from dolthub/angela/nullable

Make `IsNullable` return `true` for log and math functions where applicable

Author: angelamayxie

enginetest/queries/script_queries.go

@@ -13472,24 +13472,40 @@ select * from t1 except (
 		},
 	},
 	{
-		// https://github.com/dolthub/dolt/issues/10070
-		// https://github.com/dolthub/dolt/issues/10092
 		Name: "NOT EXISTS with nullable filter",
 		SetUpScript: []string{
 			"CREATE TABLE t0(c0 INT , c1 INT);",
 			"INSERT INTO t0(c0, c1) VALUES (1, -2);",
 			"create table t1(c0 int, primary key(c0))",
 			"insert into t1 values (1)",
+			"create table t2(c0 varchar(500), primary key(c0))",
+			"insert into t2 values ('9')",
+			"create table t3(c0 boolean, primary key(c0))",
+			"insert into t3 values(false)",
 		},
 		Assertions: []ScriptTestAssertion{
 			{
+				// https://github.com/dolthub/dolt/issues/10070
 				Query:    `SELECT * FROM t0 WHERE NOT EXISTS (SELECT 1 FROM (SELECT 1) alias0 WHERE (CASE -1 WHEN t0.c1 THEN false END));`,
 				Expected: []sql.Row{{1, -2}},
 			},
 			{
+				// https://github.com/dolthub/dolt/issues/10092
 				Query:    "select * from t1 where not exists (select 1 from (select 1) as subquery where weekday(t1.c0))",
 				Expected: []sql.Row{{1}},
 			},
+			{
+				// https://github.com/dolthub/dolt/issues/10102
+				Query:    "SELECT * FROM t2 WHERE NOT EXISTS (SELECT 1 FROM (SELECT 1) AS sub0 WHERE ASIN(t2.c0));",
+				Expected: []sql.Row{{"9"}},
+				// Postgres does not allow varchar types as inputs for ASIN
+				Dialect: "mysql",
+			},
+			{
+				// https://github.com/dolthub/dolt/issues/10157
+				Query:    "SELECT * FROM t3 WHERE NOT EXISTS (SELECT 1 FROM (SELECT 1) AS sub0 WHERE LOG2(t3.c0));",
+				Expected: []sql.Row{{0}},
+			},
 		},
 	},
 }

sql/expression/function/logarithm.go

@@ -112,7 +112,7 @@ func (*LogBase) CollationCoercibility(ctx *sql.Context) (collation sql.Collation
 
 // IsNullable implements the sql.Expression interface.
 func (l *LogBase) IsNullable() bool {
-	return l.base == float64(1) || l.base <= float64(0) || l.Child.IsNullable()
+	return true
 }
 
 // Eval implements the Expression interface.
@@ -196,7 +196,7 @@ func (*Log) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 
 // IsNullable implements the Expression interface.
 func (l *Log) IsNullable() bool {
-	return l.LeftChild.IsNullable() || l.RightChild.IsNullable()
+	return true
 }
 
 // Eval implements the Expression interface.

sql/expression/function/math.go

@@ -268,6 +268,11 @@ func (*Tan) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 	return sql.Collation_binary, 5
 }
 
+// IsNullable implements sql.Expression
+func (t *Tan) IsNullable() bool {
+	return true
+}
+
 // Eval implements sql.Expression
 func (t *Tan) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	val, err := t.EvalChild(ctx, row)
@@ -325,6 +330,11 @@ func (*Asin) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 	return sql.Collation_binary, 5
 }
 
+// IsNullable implements sql.Expression
+func (a *Asin) IsNullable() bool {
+	return true
+}
+
 // Eval implements sql.Expression
 func (a *Asin) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	val, err := a.EvalChild(ctx, row)
@@ -382,6 +392,11 @@ func (*Acos) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 	return sql.Collation_binary, 5
 }
 
+// IsNullable implements sql.Expression
+func (a *Acos) IsNullable() bool {
+	return true
+}
+
 // Eval implements sql.Expression
 func (a *Acos) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	val, err := a.EvalChild(ctx, row)
@@ -559,6 +574,11 @@ func (*Cot) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 	return sql.Collation_binary, 5
 }
 
+// IsNullable implements sql.Expression
+func (c *Cot) IsNullable() bool {
+	return true
+}
+
 // Eval implements sql.Expression
 func (c *Cot) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	val, err := c.EvalChild(ctx, row)
@@ -991,6 +1011,11 @@ func (e *Exp) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID
 	return sql.Collation_binary, 5
 }
 
+// IsNullable implements sql.Expression
+func (e *Exp) IsNullable() bool {
+	return true
+}
+
 // Eval implements the Expression interface.
 func (e *Exp) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	if e.Child == nil {