GROUP BY
1、有个店铺表,字段为区域id,设备数量,店铺名称,如下:
2、如何按区域 district 统计 每个区域的设备数量,SQL如下
SELECT district, SUM( device_num ) AS device_num FROM `t_life_shop` GROUP BY ( district )
查询结果
3、TP5.1写法
$list = $this->field('district, SUM(device_num)as device_num')->group('district')->select();