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HomeBackend DevelopmentPHP Tutorial 怎么实现这样的排序

如何实现这样的排序
在商品列表中 新添加的商品并且是上架状态的有有库存的默认排在前面,下架的库存少的或者为0的排在后面。
goods_id是自增的。大的就是最新添加的。库存字段:is_on_sale 1为上架 0为下架 库存数量:goods_number  

请问sql怎么写

------解决方案--------------------
ORDER BY `is_on_sale` DESC, `goods_id` DESC, `goods_number` DESC
------解决方案--------------------
order by is_on_sale desc,goods_number desc,goods_id desc


order by可以多重使用,优先级以先后顺序排列,
is_on_sale 为1的在上边,下架的在下边
goods_number 在上边的排序结果中 库存多的在前,
goods_id 在以前结果中,同样条件下新发的在最前

------解决方案--------------------
g.is_on_sale desc 表示上架的摆在前面
所以 上架且库存为0 的也会出现在下架的前面
如果你不想出现这种情况,就要加判断条件
g.is_on_sale and g.goods_number>0 desc
以此类推

你应该在 sql 管理器中测试好各种情况再书写代码

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