Mysql两个条件就是总共一列

Question

我有一个表suspended_bills，我希望得到总数的总和，但我希望在一个查询中得到总数。检查此查询

SELECT  date, (select sum(total) where type='bill') as bill_total, (select 
sum(total) where type='quotation') as quotation_total from suspended_bills 
group by YEAR(date),MONTH(date)

我知道这是错误的查询，但我想知道在单个查询中获取帐单和报价总和的解决方案。

Answer 1

我认为你想要条件聚合：

select YEAR(date), MONTH(date), 
       sum(case when type = 'bill' then total else 0 end) as bill_total, 
       sum(case when type = 'quotation' then total else 0 end) as quotation_total
from suspended_bills 
group by YEAR(date), MONTH(date);