thinkphp 按指定字段统计数据条数

 $shops = $Table->field('id , count(weekday) as num')->where($where)->group('weekday')->select(); 结果 Array(     [0] => Array (           [id] => 1            [num] => 3    )  [1] => Array (           [id] => 2           [num] => 3          )  ）