entc/gen: skip executing sub-query for empty set of edges (#3212)

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

@@ -178,6 +178,9 @@ func ({{ $receiver }} *{{ $builder }}) sqlAll(ctx context.Context, hooks ...quer
 				}
 				nodeids[fk] = append(nodeids[fk], nodes[i])
 			}
+			if len(ids) == 0 {
+				return nil
+			}
 			query.Where({{ $e.Type.Package }}.IDIn(ids...))
 			neighbors, err := query.All(ctx)
 			if err != nil {