dialect/sql: allow appending select columns to query

entc/gen/template/dialect/sql/select.tmpl

@@ -12,18 +12,11 @@ in the LICENSE file in the root directory of this source tree.
 
 func ({{ $receiver }} *{{ $builder }}) sqlScan(ctx context.Context, v interface{}) error {
 	rows := &sql.Rows{}
-	query, args := {{ $receiver }}.sqlQuery().Query()
+	query, args := {{ $receiver }}.sql.Query()
 	if err := {{ $receiver }}.driver.Query(ctx, query, args, rows); err != nil {
 		return err
 	}
 	defer rows.Close()
 	return sql.ScanSlice(rows, v)
 }
-
-
-func ({{ $receiver }} *{{ $builder }}) sqlQuery() sql.Querier {
-	selector := {{ $receiver }}.sql
-	selector.Select(selector.Columns({{ $receiver }}.fields...)...)
-	return selector
-}
 {{ end }}