多个Sql计数

如何解决多个Sql计数

| 我的数据库中有一个表（tbl_MatterItem），该表跟踪项目的发送和接收日期。如果尚未发送或接收，则值为NULL。我要链接到另一个表（tbl_Matter），以获取该特定项目的BillingLawyer。

BillingLawyer     ItemSent     ItemReceived
-------------     --------     ------------
   Alison         09/09/09        NULL
   Alison         10/10/10        NULL
   Alison         11/11/11       13/11/11
   Alison         12/12/12        NULL

我想为每位律师检索一行，包括他们的姓名，发送的项目数和收到的项目数。

BillingLawyer    Sent    Received
-------------    -----   --------
   Alison         4         1

以下是我到目前为止的内容：

SELECT BillingLawyer,(SELECT COUNT(disTINCT itemSent)FROM tbl_matteritem mit WHERE itemid=2 AND itemSent IS NOT NULL AND mit.ItemSent= mi.itemSent) AS [Sent],(SELECT COUNT(disTINCT itemReceived)FROM tbl_matteritem mitm WHERE itemid=2 AND itemReceived IS NOT NULL AND mitm.itemreceived = mi.itemreceived)AS Received
FROM tbl_matteritem mi JOIN tbl_matter m ON mi.matterid = m.matterid
GROUP BY BillingLawyer,ItemSent,itemreceived
ORDER BY 1

但是，我的结果显示了一条额外的记录，什么似乎是位值？：

BillingLawyer    Sent    Received
-------------    ----    --------
   Alison         0         0
   Alison         1         1
   Alison         1         0
   Alison         1         0
   Alison         1         0

有什么想法我要去哪里吗？     

解决方法

        尝试这个：

SELECT
    BillingLawyer,SUM(CASE WHEN ItemSent IS NOT NULL THEN 1 ELSE 0 END) AS Sent,SUM(CASE WHEN ItemReceived IS NOT NULL THEN 1 ELSE 0 END) AS Received
FROM
    tbl_matteritem mi
JOIN tbl_matter m ON
    mi.matterid = m.matterid
GROUP BY BillingLawyer
ORDER BY BillingLawyer

    ,        您正在

ItemSent

上分组，因此

count(distinct ItemSent

将返回1或0。毕竟，将为different5ѭ的每个不同值创建一个新组，然后将

count()

应用于该组。 如果要按

BillingLawyer

计算项目，请按

BillingLawyer

分组，而不是

ItemSent

。     ,        我想先删除

DISTINCT

，因为它将在每个日期中都有效。

SELECT BillingLawyer,(SELECT COUNT( itemSent)FROM tbl_matteritem mit WHERE itemid=2 AND itemSent IS      NOT NULL AND mit.ItemSent= mi.itemSent) AS [Sent],(SELECT COUNT( itemReceived)FROM tbl_matteritem mitm WHERE itemid=2 AND itemReceived IS NOT NULL AND mitm.itemreceived = mi.itemreceived)AS Received
FROM tbl_matteritem mi JOIN tbl_matter m ON mi.matterid = m.matterid
GROUP BY BillingLawyer,ItemSent,itemreceived
ORDER BY 1

    ,        请勿在

GROUP BY

中包括

ItemSent,itemreceived

。 仅使用

GROUP BY BillingLawyer