bugfix: Normalizing literals in SELECT is broken

go/test/endtoend/vtgate/queries/collations/collations_test.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2024 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package collations
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"vitess.io/vitess/go/test/endtoend/cluster"
+	"vitess.io/vitess/go/test/endtoend/utils"
+)
+
+func start(t *testing.T) (utils.MySQLCompare, func()) {
+	// ensure that the vschema and the tables have been created before running any tests
+	_ = utils.WaitForAuthoritative(t, keyspaceName, "t1", clusterInstance.VtgateProcess.ReadVSchema)
+	_ = utils.WaitForAuthoritative(t, keyspaceName, "t2", clusterInstance.VtgateProcess.ReadVSchema)
+
+	mcmp, err := utils.NewMySQLCompare(t, vtParams, mysqlParams)
+	require.NoError(t, err)
+
+	deleteAll := func() {
+		_, _ = utils.ExecAllowError(t, mcmp.VtConn, "set workload = oltp")
+
+		tables := []string{"t1", "t2"}
+		for _, table := range tables {
+			_, _ = mcmp.ExecAndIgnore("delete from " + table)
+		}
+	}
+
+	deleteAll()
+
+	return mcmp, func() {
+		deleteAll()
+		mcmp.Close()
+		cluster.PanicHandler(t)
+	}
+}
+
+func TestCollationTyping(t *testing.T) {
+	utils.SkipIfBinaryIsBelowVersion(t, 19, "vtgate")
+
+	mcmp, closer := start(t)
+	defer closer()
+	mcmp.Exec("insert into t1(id, name) values(1,'ß'), (2,'s'), (3,'ss')")
+	mcmp.Exec("insert into t2(id, name) values(1,'ß'), (2,'s'), (3,'ss')")
+
+	res := utils.Exec(t, mcmp.VtConn, `vexplain plan SELECT name from t1 union select name from t2`)
+	fmt.Printf("%v", res.Rows)
+	mcmp.Exec(`SELECT name from t1 union select name from t2`)
+}

go/test/endtoend/vtgate/queries/collations/main_test.go

@@ -0,0 +1,94 @@
+/*
+Copyright 2024 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package collations
+
+import (
+	_ "embed"
+	"flag"
+	"fmt"
+	"os"
+	"testing"
+
+	"vitess.io/vitess/go/test/endtoend/utils"
+
+	"vitess.io/vitess/go/mysql"
+	"vitess.io/vitess/go/test/endtoend/cluster"
+)
+
+var (
+	clusterInstance *cluster.LocalProcessCluster
+	vtParams        mysql.ConnParams
+	mysqlParams     mysql.ConnParams
+	keyspaceName    = "ks_aggr"
+	cell            = "test_aggr"
+
+	//go:embed schema.sql
+	schemaSQL string
+
+	//go:embed vschema.json
+	vschema string
+)
+
+func TestMain(m *testing.M) {
+	defer cluster.PanicHandler(nil)
+	flag.Parse()
+
+	exitCode := func() int {
+		clusterInstance = cluster.NewCluster(cell, "localhost")
+		defer clusterInstance.Teardown()
+
+		// Start topo server
+		err := clusterInstance.StartTopo()
+		if err != nil {
+			return 1
+		}
+
+		// Start keyspace
+		keyspace := &cluster.Keyspace{
+			Name:      keyspaceName,
+			SchemaSQL: schemaSQL,
+			VSchema:   vschema,
+		}
+		clusterInstance.VtGateExtraArgs = []string{"--schema_change_signal"}
+		clusterInstance.VtTabletExtraArgs = []string{"--queryserver-config-schema-change-signal"}
+		err = clusterInstance.StartKeyspace(*keyspace, []string{"-80", "80-"}, 0, false)
+		if err != nil {
+			return 1
+		}
+
+		clusterInstance.VtGateExtraArgs = append(clusterInstance.VtGateExtraArgs, "--enable_system_settings=true")
+		// Start vtgate
+		err = clusterInstance.StartVtgate()
+		if err != nil {
+			return 1
+		}
+
+		vtParams = clusterInstance.GetVTParams(keyspaceName)
+
+		// create mysql instance and connection parameters
+		conn, closer, err := utils.NewMySQL(clusterInstance, keyspaceName, schemaSQL)
+		if err != nil {
+			fmt.Println(err)
+			return 1
+		}
+		defer closer()
+		mysqlParams = conn
+
+		return m.Run()
+	}()
+	os.Exit(exitCode)
+}

go/test/endtoend/vtgate/queries/collations/schema.sql

@@ -0,0 +1,13 @@
+create table t1
+(
+    id   bigint,
+    name varchar(255) collate utf8_general_mysql500_ci,
+    primary key (id)
+) Engine = InnoDB;
+
+create table t2
+(
+    id   bigint,
+    name varchar(255) collate utf8_general_mysql500_ci,
+    primary key (id)
+) ENGINE = InnoDB;

go/test/endtoend/vtgate/queries/collations/vschema.json

@@ -0,0 +1,29 @@
+{
+  "sharded": true,
+  "vindexes": {
+    "hash": {
+      "type": "hash"
+    },
+    "unicode_loose_xxhash": {
+      "type": "unicode_loose_xxhash"
+    }
+  },
+  "tables": {
+    "t1": {
+      "column_vindexes": [
+        {
+          "column": "id",
+          "name": "hash"
+        }
+      ]
+    },
+    "t2": {
+      "column_vindexes": [
+        {
+          "column": "id",
+          "name": "hash"
+        }
+      ]
+    }
+  }
+}

go/test/endtoend/vtgate/queries/subquery/subquery_test.go

@@ -170,7 +170,10 @@ func TestSubqueryInAggregation(t *testing.T) {
 	mcmp.Exec("insert into t1(id1, id2) values(0,0),(1,1)")
 	mcmp.Exec("insert into t2(id3, id4) values(1,2),(5,7)")
 	mcmp.Exec(`SELECT max((select min(id2) from t1)) FROM t2`)
-	mcmp.Exec(`SELECT max((select group_concat(id1, id2) from t1 where id1 = 1)) FROM t1 where id1 = 1`)
+
+	// we need an alias for the subquery so that the id1 = 1 on the inside and the outside look the same and can be merged
+	mcmp.Exec(`SELECT max((select group_concat(id1, id2) from t1 where id1 = 1)) as x FROM t1 where id1 = 1`)
+
 	mcmp.Exec(`SELECT max((select min(id2) from t1 where id2 = 1)) FROM dual`)
 	mcmp.Exec(`SELECT max((select min(id2) from t1)) FROM t2 where id4 = 7`)
 

go/vt/sqlparser/ast.go

@@ -2398,7 +2398,7 @@ type (
 	FuncExpr struct {
 		Qualifier IdentifierCS
 		Name      IdentifierCI
-		Exprs     SelectExprs
+		Exprs     Exprs
 	}
 
 	// ValuesFuncExpr represents a function call.

go/vt/sqlparser/normalizer.go

@@ -21,10 +21,9 @@ import (
 
 	"vitess.io/vitess/go/mysql/datetime"
 	"vitess.io/vitess/go/sqltypes"
+	querypb "vitess.io/vitess/go/vt/proto/query"
 	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
 	"vitess.io/vitess/go/vt/vterrors"
-
-	querypb "vitess.io/vitess/go/vt/proto/query"
 )
 
 // BindVars is a set of reserved bind variables from a SQL statement
@@ -133,6 +132,9 @@ func (nz *normalizer) walkDownSelect(node, parent SQLNode) bool {
 	case *ConvertType:
 		// we should not rewrite the type description
 		return false
+	case *AliasedExpr:
+		// we only want to rewrite literals in select expressions if the column is aliased
+		return node.As.NotEmpty()
 	}
 	return nz.err == nil // only continue if we haven't found any errors
 }