feat: 去掉了批量查询时，结果为空的报错

mapping.go

@@ -247,10 +247,6 @@ func (b *Mapper) ScanRowsWithContext(ctx context.Context, target any, rows *sql.
 			// 将新实例添加到slice中
 			vf.Set(reflect.Append(vf, newStruct))
 		}
-
-		if vf.Len() == 0 { // 如果slice为空，返回 sql.ErrNoRows
-			return sql.ErrNoRows
-		}
 		return nil
 	default:
 		return errors.New("target must be a pointer to a struct or a slice of structs")
@@ -277,11 +273,11 @@ func (b *Mapper) scanRow(target reflect.Value, rows *sql.Rows) error {
 	dest := make([]interface{}, len(columns))
 	for i, colName := range columns {
 		// 拿到缓存的字段索引
-		if idx, ok := mate.DBName2IndexCache[colName]; ok {
-			dest[i] = target.FieldByIndex(idx).Addr().Interface()
-		} else {
+		idx, ok := mate.DBName2IndexCache[colName]
+		if !ok {
 			return fmt.Errorf("no corresponding field found for column %s", colName)
 		}
+		dest[i] = target.FieldByIndex(idx).Addr().Interface()
 	}
 
 	// 扫描数据