如何对包含聚合或子查询的表达式执行聚合函数？

I have a query like this

我有这样的查询

SELECT Id
    ,sum(CASE 
            WHEN ErrorId NOT IN (                        
                    ,10                     
                    ,11                     
                    ,12
                    ,13
                    )
                THEN 1
            ELSE 0
            END) errorCount
FROM Table 
group by Id

I don't like the hardcoded list of ids and I have a simple query that will get me what I want

我不喜欢硬编码的ID列表,我有一个简单的查询,可以得到我想要的东西

SELECT Id
    ,sum(CASE 
            WHEN ErrorId NOT IN (
              select ErrorId from Errors where ErrorCategory =  'Ignore_Error'
                    )
                THEN 1
            ELSE 0
            END) errorCount
FROM Table 
group by Id

However when I try this I get

但是,当我尝试这个时,我得到了

Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

无法对包含聚合或子查询的表达式执行聚合函数。

What is my best way ahead?

我未来的最佳方式是什么?

1 个解决方案

#1

As stated in error message you cannot use Aggregate function on top of Sub-Query

如错误消息中所述,您不能在子查询之上使用聚合函数

Here is the correct way to do it

这是正确的方法

SELECT t.Id,
       Count(e.ErrorId) errorCount
FROM   Table t
       LEFT JOIN Errors e
              ON t.ErrorId = e.ErrorId
                 AND e.ErrorCategory = 'Ignore_Error'
GROUP  BY t.Id

Another way will be using Outer Apply

另一种方法是使用外部应用

SELECT t.Id,
       Count(ou.ErrorId) errorCount
FROM   Table t
       OUTER apply (SELECT e.ErrorId
                    FROM   Errors e
                    WHERE  t.ErrorId = e.ErrorId
                           AND e.ErrorCategory = 'Ignore_Error') ou
GROUP  BY t.id

#1