Question

我有一个显示客户交易的表。我的目标是列出最新交易的客户（MAX trans_Date）

表格如下所示

**tblTransaction**
transId   custServId  transDate
  10          3       2013-12-24 11:10:57.390     
  11          4       2013-12-25 11:10:57.390
  12          5       2013-12-26 11:10:57.390
  13          6       2013-12-27 11:10:57.390

**tblCustomerService**
 custServId   custId    custServices
   3            2       Bill Payment
   4            2       Recharge
   5            3       Renewal
   6            4       BillPayment

**tblCustomer**
 custId      custName    custAddress
  2           Arun        test1
  3           Rahul       test2
  4           Kumar       test3

期望的结果应该是

 custId   custName    LastTransactionDate
   2        Arun      2013-12-25 11:10:57.390
   3        Rahul     2013-12-26 11:10:57.390
   4        Kumar     2013-12-27 11:10:57.390

我已经尝试了以下查询，但我没有得到所需的结果。这些值都在显示

Select c.Cust_CustID as custId,
c.Cust_CustName as custName,
c.Cust_Mobno as custMob,
c.Cust_EmailID as custEmail,
Max(e.Enq_EnqDate) as transactionDate   
from dbo.EP_Enquiry e
inner join  dbo.EP_CustomerServices cs on cs.CustServ_CustServID=e.CustServ_CustServID
inner join dbo.EP_Customer c on c.Cust_CustID=cs.CustServ_CustID
group by c.Cust_CustID,c.Cust_CustName,c.Cust_Mobno,c.Cust_EmailID,e.Enq_EnqID
order by transactionDate desc

Answer 1

尝试此查询：

SELECT
   tblCustomer.*,
   T.MaxDate
FROM tblCustomer
LEFT JOIN
 ( SELECT tblCustomerService.custId,
          MAX(tblTransaction.transDate) as MaxDate
   FROM tblTransaction
   JOIN tblCustomerService on 
        tblCustomerService.custServId=tblTransaction.custServId
   GROUP BY tblCustomerService.custId
  ) as T 
     on tblCustomer.custId = T.custId

SQLFiddle demo

Answer 2

您可以这样使用：

SELECT TC.custID,TC.custName, TTRANS.transDate FROM 
tblTransaction TTRANS
INNER JOIN 
tblCustomerService TCS ON TTRANS.custServId   = TCS.custServId  
INNER JOIN tblCustomer TC ON TCS.custId     = TC.custId    
WHERE TTRANS.transDate  = (SELECT MAX(transDate) FROM tblTransaction b WHERE TCS.custId = b.custId)

如何使用MAX进行GROUP BY（DATE）

2 个答案: