Sql 按嵌套选择分组时列名无效

我有以下代码，当我按原样运行时，它将返回我想要的数据：

select tagid, 
  (select TOP 1 Locations.CostCenter
  from item
  inner join transactions on transactions.itemid = item.id 
  inner join recvlocationmapping on recvlocationid = transactions.locationid 
  left outer join locations on locations.id = servicelocationid  
  where tagid = c.TagID
  and costcenter != '' 
  and Costcenter is not null 
  order by transdate desc) as CostCenter
from item as c where createddate between '07-01-2012' and '07-05-2012' 

当我想将GROUPBY添加到其中一列时，问题就出现了。然后它抛出一个错误，表示该列不存在，但当我运行查询时，没有按列和名称显示的组

以下是我遇到问题的分组代码：

select Count(tagid), 
  (select TOP 1 Locations.CostCenter
  from item
  inner join transactions on transactions.itemid = item.id 
  inner join recvlocationmapping on recvlocationid = transactions.locationid 
  left outer join locations on locations.id = servicelocationid  
  where tagid = c.TagID
  and costcenter != '' 
  and Costcenter is not null 
  order by transdate desc) as CostCenter
from item as c where createddate between '07-01-2012' and '07-05-2012'
group by CostCenter

---

我认为如何返回数据是一个问题，但我对SQL的了解不够，无法确定如何修复它。

在

select…

部分声明的别名不能在

分组方式中使用。您必须在
分组方式中复制嵌套的select，或者使用类似的方法：

select Count(q.tagid), q.CostCenter
from
    (select 
       tagid, 
       (select TOP 1 Locations.CostCenter
           from item
           inner join transactions on transactions.itemid = item.id 
           inner join recvlocationmapping on recvlocationid = transactions.locationid 
           left outer join locations on locations.id = servicelocationid  
           where tagid = c.TagID
           and costcenter != '' 
           and Costcenter is not null 
           order by transdate desc
       ) as CostCenter
       from item as c where createddate between '07-01-2012' and '07-05-2012'
    ) q
group by q.CostCenter

在
select…
部分中声明的别名不能在
分组依据中使用。您必须在
分组方式中复制嵌套的select，或者使用类似的方法：

select Count(q.tagid), q.CostCenter
from
    (select 
       tagid, 
       (select TOP 1 Locations.CostCenter
           from item
           inner join transactions on transactions.itemid = item.id 
           inner join recvlocationmapping on recvlocationid = transactions.locationid 
           left outer join locations on locations.id = servicelocationid  
           where tagid = c.TagID
           and costcenter != '' 
           and Costcenter is not null 
           order by transdate desc
       ) as CostCenter
       from item as c where createddate between '07-01-2012' and '07-05-2012'
    ) q
group by q.CostCenter

您可以在此处使用T-SQL
APPLY
功能，它与您使用的相关子查询类似，但可以多次引用，而无需重复相同的代码，如果需要，还可以返回多个列/行

SELECT  COUNT(tagid), 
        CostCenter
FROM    item as c 
        OUTER APPLY
        (   SELECT  TOP 1 Locations.CostCenter
            FROM    item
                    INNER JOIN transactions 
                        ON transactions.itemid = item.id 
                    INNER JOIN recvlocationmapping 
                        ON recvlocationid = transactions.locationid 
                    INNER JOIN locations 
                        ON locations.id = servicelocationid  
            WHERE   tagid = c.TagID
            AND     costcenter != '' 
            ORDER BY transdate DESC
        ) AS CostCenter
WHERE   createddate BETWEEN '07-01-2012' AND '07-05-2012'
GROUP BY CostCenter

我还对您的子查询做了一些修改，我将位置上的
左连接
更改为
内部连接
，因为您有
，而且成本中心不为空
，因此不需要
左连接
，而
内部连接
的性能会更好。其次，
和成本中心不为空
在
和成本中心之后是多余的！=''因为
NULL！=''

编辑

经过进一步思考，我认为您可以完全删除其中的相关子查询，并使用
连接获得相同的结果。这将提高执行效率：

;WITH CostCenter AS
(   SELECT  TagID, CostCenter, ROW_NUMBER() OVER(PARTITION BY TagID ORDER BY TransDate DESC) AS RowNumber
    FROM    item
            INNER JOIN transactions 
                ON transactions.itemid = item.id 
            INNER JOIN recvlocationmapping 
                ON recvlocationid = transactions.locationid 
            INNER JOIN locations 
                ON locations.id = servicelocationid  
    WHERE   costcenter != '' 
)
SELECT  COUNT(TagID), CostCenter
FROM    Item
        INNER JOIN CostCenter
            ON Item.TagID = CostCenter.TagID
            AND RowNumber = 1
WHERE   createddate BETWEEN '07-01-2012' AND '07-05-2012'
GROUP BY CostCenter

您可以在此处使用T-SQL
APPLY
功能，它与您使用的相关子查询类似，但可以多次引用，而无需重复相同的代码，如果需要，还可以返回多个列/行

SELECT  COUNT(tagid), 
        CostCenter
FROM    item as c 
        OUTER APPLY
        (   SELECT  TOP 1 Locations.CostCenter
            FROM    item
                    INNER JOIN transactions 
                        ON transactions.itemid = item.id 
                    INNER JOIN recvlocationmapping 
                        ON recvlocationid = transactions.locationid 
                    INNER JOIN locations 
                        ON locations.id = servicelocationid  
            WHERE   tagid = c.TagID
            AND     costcenter != '' 
            ORDER BY transdate DESC
        ) AS CostCenter
WHERE   createddate BETWEEN '07-01-2012' AND '07-05-2012'
GROUP BY CostCenter

我还对您的子查询做了一些修改，我将位置上的
左连接
更改为
内部连接
，因为您有
，而且成本中心不为空
，因此不需要
左连接
，而
内部连接
的性能会更好。其次，
和成本中心不为空
在
和成本中心之后是多余的！=''因为
NULL！=''

编辑

经过进一步思考，我认为您可以完全删除其中的相关子查询，并使用
连接获得相同的结果。这将提高执行效率：

;WITH CostCenter AS
(   SELECT  TagID, CostCenter, ROW_NUMBER() OVER(PARTITION BY TagID ORDER BY TransDate DESC) AS RowNumber
    FROM    item
            INNER JOIN transactions 
                ON transactions.itemid = item.id 
            INNER JOIN recvlocationmapping 
                ON recvlocationid = transactions.locationid 
            INNER JOIN locations 
                ON locations.id = servicelocationid  
    WHERE   costcenter != '' 
)
SELECT  COUNT(TagID), CostCenter
FROM    Item
        INNER JOIN CostCenter
            ON Item.TagID = CostCenter.TagID
            AND RowNumber = 1
WHERE   createddate BETWEEN '07-01-2012' AND '07-05-2012'
GROUP BY CostCenter

您可能需要将整个子句放入组中；我认为它不能使用别名。您可能需要将整个子句放到GROUP BY中；我认为它不能用别名。