如何将两个带有有子句的查询合并为一个？答案

【问题标题】：How can I combine two queries with a having clause into one?如何将两个带有有子句的查询合并为一个？
【发布时间】：2016-01-07 14:18:35
【问题描述】：

希望你能帮我解决这两个查询：

select count(distinct ID), sum(AMOUNT) 
from SALES 
where YEAR(SALEDATE) = '2015' and SALETYPE ='CASH'
group by CUSTOMER having sum(AMOUNT) >=500;

select count(distinct ID), sum(AMOUNT) 
from SALES 
where YEAR(SALEDATE) = '2015' and SALETYPE ='CREDITCARD'
group by CUSTOMER having sum(AMOUNT) >=1000;

将它们合二为一的最佳方法是什么？我的目标是选择客户以现金支付超过 500 美元或通过信用卡支付超过 1000 美元的所有案例。

非常感谢您的帮助。

【问题讨论】：

标签： mysql sql having

【解决方案1】：

在你的情况下，你可以使用这个例子：

select  count(distinct ID), 
        sum(AMOUNT) 
from    SALES 
where   YEAR(SALEDATE) = '2015' 
    and SALETYPE ='CASH' 
group by CUSTOMER 
having  sum(AMOUNT) >=500;

UNION

select  count(distinct ID), 
        sum(AMOUNT) 
from    SALES 
where   YEAR(SALEDATE) = '2015' 
    and SALETYPE ='CREDITCARD' 
group by CUSTOMER 
having  sum(AMOUNT) >=1000;

OR UNION ALL，如果你想要所有没有distinct的记录。

select  count(distinct ID), 
        sum(AMOUNT) 
from    SALES 
where   YEAR(SALEDATE) = '2015' 
    and SALETYPE ='CASH' 
group by CUSTOMER 
having  sum(AMOUNT) >=500;

UNION ALL

select  count(distinct ID), 
        sum(AMOUNT) 
from    SALES 
where   YEAR(SALEDATE) = '2015' 
        and SALETYPE ='CREDITCARD' 
group by CUSTOMER 
having  sum(AMOUNT) >=1000;

【讨论】：

【解决方案2】：

在having 子句中使用条件聚合：

select count(distinct ID), sum(AMOUNT) 
from SALES 
where YEAR(SALEDATE) = '2015' and 
      SALETYPE IN ('CASH', 'CREDITCARD')
group by CUSTOMER
having sum(case when SALETYPE = 'CASH' then AMOUNT end) >= 50 OR
       sum(case when SALETYPE = 'CREDITCARD' then AMOUNT end) >= 1000;

【讨论】：

非常感谢。你的书看起来也很有用。但是，不应该是 OR 而不是 AND 吗？ having sum(case when SALETYPE = 'CASH' then AMOUNT end) >= 50 OR(!) sum(case when SALETYPE = 'CREDITCARD' then AMOUNT end) >= 1000;
@user1269766 。 . .是的。我读过这个问题，希望同时满足这两个条件。