需求:
- 获取设备列表
- 汇总每个设备下的货道产品的总数量
- 可以通过货道产品的总数量排序
设备表 device
货道表 channel
直接上SQL语句
SELECT d.*,b.goods_num FROM device as d
LEFT JOIN (
SELECT sum(goods_num) as goods_num ,device_id
FROM channel
WHERE GROUP BY device_id
) as b ON b.device_id = d.device_id
ORDER BY goods_num ASC
LIMIT 0,10