Question

我有一个包含Date列和Amount列的表：

CustID    Date        Amount
1         20150301    10000
1         20150302    5000
1         20150303    15000
2         20150208    9000
2         20150201    5000
2         20150202    6000

我希望Amount在某个日期之后设置为Date。更新后，它应如下所示：

CustID    Date        Amount
1         20150301    10000
1         20150302    0
1         20150303    0
2         20150208    0
2         20150201    5000
2         20150202    0

我该怎么做？

Answer 1

我会使用窗口函数来执行此操作：

with toupdate as (
      select t.*, min(date) over (partition by CustId) as mindate
      from table t
     )
update toupdate
    set amount = 0
    where date > mindate;

Answer 2

您可以使用以下查询检查date是否不等于MIN(Date)：

UPDATE Mytable
SET Amount = 0
FROM Mytable AS t
WHERE [date] <> (SELECT MIN([Date]) 
                 FROM Mytable
                 WHERE CustId = t.CustID)

或者使用CTE：

;WITH MIN_CTE AS (
   SELECT MIN([Date]) AS MinDate, CustID
   FROM Mytable 
   GROUP BY CustID
)
UPDATE Mytable
SET Amount = 0
FROM Mytable AS t
INNER JOIN MIN_CTE AS c ON t.CustID = c.CustID
WHERE t.[Date] <> c.MinDate

Answer 3

我们可以做更新但是在这里我在select语句中显示相同的row_number和MIN函数...

declare @t table (custid int,datet date,Amount int) 
insert into @t(custid,datet,Amount)values (1,'20150301',10000)
insert into @t(custid,datet,Amount)values (1,'20150302',5000)
insert into @t(custid,datet,Amount)values (1,'20150303',15000)
insert into @t(custid,datet,Amount)values (2,'20150208',9000)
insert into @t(custid,datet,Amount)values (2,'20150201',5000)
insert into @t(custid,datet,Amount)values (2,'20150202',4000)

;with CTE AS
(
select *,ROW_NUMBER()OVER(PARTITION BY custid order by datet )RN from @t
)
Select custid,datet,case when RN = 1 then amount ELSE 0 END Amt from cte

OR

;with CTE AS
(
select *,min(datet)OVER(PARTITION BY custid )RN from @t
)
Select custid,datet,case when RN = MIN(datet) then amount ELSE 0 END Amt from cte
group by  custid,datet,Amount,RN

根据另一个字段中的日期将表字段设置为零

3 个答案: