mysql 力扣，5452. Sales by Day of the Week

skywander0

于 2020-06-16 17:12:32 发布

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本文链接：https://blog.youkuaiyun.com/qq_42232193/article/details/106791232

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Sales by Day of the Week
https://leetcode-cn.com/problems/sales-by-day-of-the-week/

翻译过来的意思就是说统计每个item_category每个星期的销量，结果如下所示：

####这题感觉不难，就是一个计算日期为星期的函数
####dayname可以直接将日期换成星期
select item_category category,
       sum(if(dayname(b.order_date)='Monday',b.quantity,0) )Monday,
       sum(if(dayname(b.order_date)='Tuesday',b.quantity,0) )Tuesday,
       sum(if(dayname(b.order_date)='Wednesday',b.quantity,0)) Wednesday,
       sum(if(dayname(b.order_date)='Thursday',b.quantity,0) )Thursday,
       sum(if(dayname(b.order_date)='Friday',b.quantity,0) )Friday,
       sum(if(dayname(b.order_date)='Saturday',b.quantity,0)) Saturday,
       sum(if(dayname(b.order_date)='Sunday',b.quantity,0) )Sunday
from Items a left join Orders b
on  
a.item_id = b.item_id
group by  b.item_category
order by  b.item_category