remove redundant codes

Author: BetaCat0

builder_union.go

@@ -32,25 +32,6 @@ func (b *Builder) unionWriteTo(w Writer) error {
 }
 fmt.Fprint(w, "(")
 
-// switch b.dialect {
-// case ORACLE, MSSQL:
-//	// if dialect is Oracle or Mssql, we need to make a copy of current context
-//	// coz the result of current will turn into a sub-query when building LIMIT query
-//	tw := NewWriter()
-//	if err := current.selectWriteTo(tw); err != nil {
-//	return err
-//	}
-//
-//	fmt.Fprintf(w, tw.writer.String())
-//	w.(*BytesWriter).args = append(w.(*BytesWriter).args, tw.args...)
-// case MYSQL, SQLITE, POSTGRES:
-//	if err := current.selectWriteTo(w); err != nil {
-//	return err
-//	}
-// default:
-//	return ErrNotSupportType
-// }
-
 if err := current.selectWriteTo(w); err != nil {
 return err
 }