MySQL 联合所有列

Question

我有一个用于案例的 mysql 表。它有每个产品的产品名称，可以有多个不同状态的记录。

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SELECT 
product , count(*) as totalopen
FROM cases
where status='OPEN'
group by product
union all
SELECT 
product , count(*) as totalclosed
FROM cases
where status='CLOSED'
group by product

它给我的结果是

但我想要的结果是

我在查询中到底遗漏了什么。任何帮助将不胜感激。

Answer 1

通过使用 Inner Join 尝试以下代码:

Select a.product, totalopen , totalclosed
from (
SELECT 
product , count(*) as totalopen
FROM cases
where status='OPEN'
group by product ) a
inner join (
SELECT 
product ,count(*) as totalclosed
FROM cases
where status='CLOSED'
group by product ) b
on a.product = b.product.

更新:-

对于只有一条记录，状态只有CLOSED或OPEN的产品，使用Full Outer Join代替内部连接 作为下一个:-

Select isnull(a.product,b.product) product, isnull(totalopen,0) totalopen , isnull(totalclosed,0) totalclosed
from (
SELECT 
product , count(*) as totalopen
FROM cases
where status='OPEN'
group by product ) a
full outer join (
SELECT 
product ,count(*) as totalclosed
FROM cases
where status='CLOSED'
group by product ) b
on a.product = b.product