[英]SQL Query for Count value from the latest date
我需要一個返回ff的查詢:
示例表:
ID Name Date Count
1 Adj 09/29/2012 2
2 Adj 09/30/2012 4
3 Ped 09/29/2012 -1
4 Ped 09/30/2012 5
5 Mel 09/29/2012 3
6 Mel 09/30/2012 -1
7 Rod 09/30/2012 7
8 Ney 09/30/2012 -1
9 Jin 09/29/2012 -1
10 Jin 09/30/2012 -1
所需輸出:
Name Count
Adj 4
Ped 5
Mel 3
Rod 7
Ney 0
Jin 0
我對如何在SQL中實現此方法感到非常困惑,因為我只知道簡單的查詢。
關於如何對此進行查詢的任何想法? 謝謝。
順便說一句,對不起,我忘了包括在內。 我正在使用SQL Server 2000。
嘗試這個
select A.name, isnull(T.[Count], 0) as [Count]
from (select distinct T.name from table1 as T) as A
outer apply
(
select top 1 T.[Count]
from table1 as T
where T.name = A.name and T.[Count] <> -1
order by T.[date] desc
) as T
order by A.name asc
更新 :對於SQL 2000,您可以使用像這樣的查詢
select A.name, isnull(T1.[Count], 0) as [Count]
from
(
select T.name, max(case when T.[Count] <> -1 then T.[date] else null end) as [date]
from table1 as T
group by T.name
) as A
left outer join table1 as T1 on T1.name = A.name and T1.[date] = A.[date]
但這取決於您對name, [date]
列具有唯一約束的建議
另一個
Select * from
(
Select Test.name,[Count]
from TEST
Join(
Select name, MAX(Date) as Date from TEST
where [Count]<>-1
Group by Name) a
on a.Name=test.Name and a.Date=Test.Date
UNION
Select Distinct name,0 from test o where not Exists(Select * from test where name=o.Name and [count]<>-1)
) res
order by Name
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