fix: mysql quoting issues

dialect_common.go

@@ -29,17 +29,22 @@ func (commonDialect) Lock(fn func() error) error {
 	return fn()
 }
 
-func (commonDialect) Quote(key string) string {
-	parts := strings.Split(key, ".")
+func quoteIdentifiers(s, quote string) string {
+	parts := strings.Split(s, ".")
 
 	for i, part := range parts {
-		part = strings.Trim(part, `"`)
+		part = strings.Trim(part, quote)
 		part = strings.TrimSpace(part)
 
-		parts[i] = fmt.Sprintf(`"%v"`, part)
+		parts[i] = quote + part + quote
 	}
 
 	return strings.Join(parts, ".")
+
+}
+
+func (commonDialect) Quote(key string) string {
+	return quoteIdentifiers(key, `"`)
 }
 
 func genericCreate(c *Connection, model *Model, cols columns.Columns, quoter quotable) error {

dialect_mysql.go

@@ -43,7 +43,7 @@ func (m *mysql) DefaultDriver() string {
 }
 
 func (mysql) Quote(key string) string {
-	return fmt.Sprintf("`%s`", key)
+	return quoteIdentifiers(key, "`")
 }
 
 func (m *mysql) Details() *ConnectionDetails {

dialect_mysql_test.go

@@ -244,3 +244,12 @@ func (s *MySQLSuite) Test_MySQL_DDL_Schema() {
 	err = PDB.Dialect.DumpSchema(f)
 	r.Error(err)
 }
+
+func Test_MySQL_Quote(t *testing.T) {
+	r := require.New(t)
+
+	m := &mysql{}
+	r.Equal("`table_name`", m.Quote("table_name"))
+	r.Equal("`schema`.`table_name`", m.Quote("schema.table_name"))
+	r.Equal("`schema`.`table_name`", m.Quote(m.Quote("schema.table_name")))
+}