Question

我正在尝试查找报告中出现过一次或更少次数的项目。我知道要找到每个项目有多少次，我会用它。

select COUNT(VP.VendorPartID)
from Purchasing.PurchaseOrder PO with (nolock)
    inner join dbo.tblVendor V with (nolock)
        on PO.VendorID=V.VendorID
    inner join Purchasing.PurchaseOrderItem POI with (nolock)
        on PO.PurchaseOrderID=POI.PurchaseOrderID
    inner join Purchasing.VendorPart VP with (nolock)
        on POI.VendorPartID=VP.VendorPartID
where V.ProductTypeID=4
group by PO.PurchaseOrderID

但我尝试将其嵌套在另一个查询中，以便能够设置它必须出现1次或更少，并且它说有错误，因为

“子查询返回的值超过1。当这个值不允许时子查询跟随=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或当子查询用作表达。“

我这样做了，我猜这可能是非常错的，哈哈。

select VP.VendorPartID,VP.VendorPartDescription
from Purchasing.PurchaseOrder PO with (nolock)
    inner join dbo.tblVendor V with (nolock)
        on PO.VendorID=V.VendorID
    inner join Purchasing.PurchaseOrderItem POI with (nolock)
        on PO.PurchaseOrderID=POI.PurchaseOrderID
    inner join Purchasing.VendorPart VP with (nolock)
        on POI.VendorPartID=VP.VendorPartID
where (
        select COUNT(VP.VendorPartID)
        from Purchasing.PurchaseOrder PO with (nolock)
            inner join dbo.tblVendor V with (nolock)
                on PO.VendorID=V.VendorID
            inner join Purchasing.PurchaseOrderItem POI with (nolock)
                on PO.PurchaseOrderID=POI.PurchaseOrderID
            inner join Purchasing.VendorPart VP with (nolock)
                on POI.VendorPartID=VP.VendorPartID
        where V.ProductTypeID=4
        group by PO.PurchaseOrderID
        ) < 2
group by VP.VendorPartID,VP.VendorPartDescription

期望的结果将是

VendorPartID  VendorPartDescription  
001           name 1                 
002           name 2                 
003           name 3

只显示那些在采购订单上出现过一次的那些。

Answer 1

HAVING子句是您需要的 - 它就像WHERE子句，但适用于GROUP BY

产生效果：

Select Id, count(othercolumn)
from sometable
where somecolumn = something
group by Id
having (count(somecolumn) < 2)

Answer 2

如果这对您的计数非常有用：

select COUNT(VP.VendorPartID)
from Purchasing.PurchaseOrder PO with (nolock)
    inner join dbo.tblVendor V with (nolock)
        on PO.VendorID=V.VendorID
    inner join Purchasing.PurchaseOrderItem POI with (nolock)
        on PO.PurchaseOrderID=POI.PurchaseOrderID
    inner join Purchasing.VendorPart VP with (nolock)
        on POI.VendorPartID=VP.VendorPartID
where V.ProductTypeID=4
group by PO.PurchaseOrderID`

然后只需添加having子句：

select PO.PurchaseOrderID, COUNT(VP.VendorPartID)
from Purchasing.PurchaseOrder PO with (nolock)
    inner join dbo.tblVendor V with (nolock)
        on PO.VendorID=V.VendorID
    inner join Purchasing.PurchaseOrderItem POI with (nolock)
        on PO.PurchaseOrderID=POI.PurchaseOrderID
    inner join Purchasing.VendorPart VP with (nolock)
        on POI.VendorPartID=VP.VendorPartID
where V.ProductTypeID=4
group by PO.PurchaseOrderID
having COUNT(VP.VendorPartID) <= 1

Answer 3

尝试此操作可让您根据计数获取详细信息

select * from
(select VP.VendorPartID,VP.VendorPartDescription,COUNT(VP.VendorPartID) as PartCount
  from Purchasing.PurchaseOrder PO with (nolock)
    inner join dbo.tblVendor V with (nolock)
      on PO.VendorID=V.VendorID
    inner join Purchasing.PurchaseOrderItem POI with (nolock)
      on PO.PurchaseOrderID=POI.PurchaseOrderID
    inner join Purchasing.VendorPart VP with (nolock)
      on POI.VendorPartID=VP.VendorPartID
group by
  VP.VendorPartID,VP.VendorPartDescription) as qCounts
where qCounts.PartCount < 2

Where子句中的SQL Count

3 个答案: