Failing tests for nullability in result schemas

Author: zachmu

enginetest/evaluation.go

@@ -868,6 +868,7 @@ func checkResultsDefault(t *testing.T, ctx *sql.Context, expected []sql.Row, exp
 type resultSchemaCol struct {
 	Name string
 	Type querypb.Type
+	Nullable bool
 }
 
 func simplifyResultSchema(s sql.Schema) []resultSchemaCol {
@@ -876,6 +877,7 @@ func simplifyResultSchema(s sql.Schema) []resultSchemaCol {
 		fields[i] = resultSchemaCol{
 			Name: c.Name,
 			Type: c.Type.Type(),
+			Nullable: c.Nullable,
 		}
 	}
 	return fields

enginetest/queries/queries.go

@@ -1072,6 +1072,17 @@ var QueryTests = []QueryTest{
 		Query:    "select sum(1) from emptytable",
 		Expected: []sql.Row{{nil}},
 	},
+	{
+		Query:    "select sum(1) as s from emptytable",
+		Expected: []sql.Row{{nil}},
+		ExpectedColumns: sql.Schema{
+			{
+				Name: "s",
+				Type: types.Float64,
+				Nullable: true,
+			},
+		},
+	},
 	{
 		Query:    "select * from (select count(*) from xy) dt",
 		Expected: []sql.Row{{4}},