Fix prepared statements in column specs

go/mysql/conn.go

@@ -926,9 +926,15 @@ func (c *Conn) handleNextCommand(handler Handler) error {
 			prepare.BindVars = make(map[string]*querypb.BindVariable, paramsCount)
 		}
 
+		bindVars := make(map[string]*querypb.BindVariable, paramsCount)
+		for i := uint16(0); i < paramsCount; i++ {
+			parameterID := fmt.Sprintf("v%d", i+1)
+			bindVars[parameterID] = &querypb.BindVariable{}
+		}
+
 		c.PrepareData[c.StatementID] = prepare
 
-		fld, err := handler.ComPrepare(c, queries[0])
+		fld, err := handler.ComPrepare(c, queries[0], bindVars)
 
 		if err != nil {
 			if werr := c.writeErrorPacketFromError(err); werr != nil {

go/mysql/fakesqldb/server.go

@@ -430,7 +430,7 @@ func (db *DB) comQueryOrdered(query string) (*sqltypes.Result, error) {
 }
 
 // ComPrepare is part of the mysql.Handler interface.
-func (db *DB) ComPrepare(c *mysql.Conn, query string) ([]*querypb.Field, error) {
+func (db *DB) ComPrepare(c *mysql.Conn, query string, bindVars map[string]*querypb.BindVariable) ([]*querypb.Field, error) {
 	return nil, nil
 }
 

go/mysql/server.go

@@ -101,7 +101,7 @@ type Handler interface {
 
 	// ComPrepare is called when a connection receives a prepared
 	// statement query.
-	ComPrepare(c *Conn, query string) ([]*querypb.Field, error)
+	ComPrepare(c *Conn, query string, bindVars map[string]*querypb.BindVariable) ([]*querypb.Field, error)
 
 	// ComStmtExecute is called when a connection receives a statement
 	// execute query.

go/mysql/server_test.go

@@ -221,7 +221,7 @@ func (th *testHandler) ComQuery(c *Conn, query string, callback func(*sqltypes.R
 	return nil
 }
 
-func (th *testHandler) ComPrepare(c *Conn, query string) ([]*querypb.Field, error) {
+func (th *testHandler) ComPrepare(c *Conn, query string, bindVars map[string]*querypb.BindVariable) ([]*querypb.Field, error) {
 	return nil, nil
 }
 

go/test/endtoend/preparestmt/stmt_methods_test.go

@@ -205,6 +205,46 @@ func reconnectAndTest(t *testing.T) {
 
 }
 
+// TestColumnParameter query database using column
+// parameter.
+func TestColumnParameter(t *testing.T) {
+	defer cluster.PanicHandler(t)
+	dbo := Connect(t)
+	defer dbo.Close()
+
+	id := 1000
+	parameter1 := "param1"
+	message := "TestColumnParameter"
+	insertStmt := "INSERT INTO " + tableName + " (id, msg, keyspace_id) VALUES (?, ?, ?);"
+	values := []interface{}{
+		id,
+		message,
+		2000,
+	}
+	exec(t, dbo, insertStmt, values...)
+
+	var param, msg string
+	var recID int
+
+	selectStmt := "SELECT COALESCE(?, id), msg FROM " + tableName + " WHERE msg = ? LIMIT ?"
+
+	results1, err := dbo.Query(selectStmt, parameter1, message, 1)
+	require.Nil(t, err)
+	require.True(t, results1.Next())
+
+	results1.Scan(&param, &msg)
+	assert.Equal(t, parameter1, param)
+	assert.Equal(t, message, msg)
+
+	results2, err := dbo.Query(selectStmt, nil, message, 1)
+	require.Nil(t, err)
+	require.True(t, results2.Next())
+
+	results2.Scan(&recID, &msg)
+	assert.Equal(t, id, recID)
+	assert.Equal(t, message, msg)
+}
+
 // TestWrongTableName query database using invalid
 // tablename and validate error.
 func TestWrongTableName(t *testing.T) {

go/vt/vtgate/plugin_mysql_server.go

@@ -218,7 +218,7 @@ func (vh *vtgateHandler) ComQuery(c *mysql.Conn, query string, callback func(*sq
 }
 
 // ComPrepare is the handler for command prepare.
-func (vh *vtgateHandler) ComPrepare(c *mysql.Conn, query string) ([]*querypb.Field, error) {
+func (vh *vtgateHandler) ComPrepare(c *mysql.Conn, query string, bindVars map[string]*querypb.BindVariable) ([]*querypb.Field, error) {
 	var ctx context.Context
 	var cancel context.CancelFunc
 	if *mysqlQueryTimeout != 0 {
@@ -252,7 +252,7 @@ func (vh *vtgateHandler) ComPrepare(c *mysql.Conn, query string) ([]*querypb.Fie
 		}
 	}()
 
-	session, fld, err := vh.vtg.Prepare(ctx, session, query, make(map[string]*querypb.BindVariable))
+	session, fld, err := vh.vtg.Prepare(ctx, session, query, bindVars)
 	err = mysql.NewSQLErrorFromError(err)
 	if err != nil {
 		return nil, err

go/vt/vtgate/plugin_mysql_server_test.go

@@ -51,7 +51,7 @@ func (th *testHandler) ComQuery(c *mysql.Conn, q string, callback func(*sqltypes
 	return nil
 }
 
-func (th *testHandler) ComPrepare(c *mysql.Conn, q string) ([]*querypb.Field, error) {
+func (th *testHandler) ComPrepare(c *mysql.Conn, q string, b map[string]*querypb.BindVariable) ([]*querypb.Field, error) {
 	return nil, nil
 }