Question

我有下表

Key    Year_month    Ammount  
1      201612        100  
1      201701        120
2      201605        1000
2      201608        800
3      201705        500

我需要使用最低的year_month值

为每个键选择一行

例如：这应该是查询的结果

Key    Year_month    Ammount  
1      201612        100  
2      201605        1000
3      201705        500

问题是我不确定如何做到这一点，我尝试使用

SELECT   
      KEY,
      YEAR_MONTH,  
      AMMOUNT
FROM TABLE AS T1
WHERE YEAR_MONTH =(SELECT TOP 1 YEAR_MONTH FROM TABLE WHERE KEY = T1.KEY)

但这不起作用

Answer 1

Select DT.* FROM Data_Table DT
    JOIN
       ( SELECT [KEY], Min(Year_month) AS MinYM FROM Data_Table GROUP BY [KEY] ) DX
        ON DX.[KEY]= DT.[KEY] AND DX.MinYM = DT.Year_month ;

Answer 2

另一种方法

<span th:if="${#arrays.contains({'fr','en','bl'}, entry.value)}">

返回

declare @table table ([key] int, year_month int, amount int)

insert into @table ([key], year_month, amount)
values (1, 201612, 100),  
       (1, 201701, 120),
       (2, 201605, 1000),
       (2, 201608, 800),
       (3, 201705, 500)


select t.*,
       (select t2.amount from @table t2 where t2.[key] = t.[key] and t2.year_month = t.year_month) as amount
from   ( select [key], min(year_month) as year_month
         from   @table 
         group by [key]
       ) t

Answer 3

试试这个

[19:02:48]  build dev finished in 13.28 s
> cordova run android

You have been opted out of telemetry. To change this, run: cordova telemetry on.
Android Studio project detected

ANDROID_HOME=G:\dl\Android\sdk
JAVA_HOME=C:\Program Files\Java\jdk1.8.0_162
studio
[19:02:53]  lint finished in 4.70 s
Starting a Gradle Daemon (subsequent builds will be faster)

:wrapper


BUILD SUCCESSFUL
 in 13s
1 actionable task: 1 executed
Subproject Path: CordovaLib
Subproject Path: app
Exception in thread "main"
java.lang.NullPointerException
        at org.gradle.wrapper.PathAssembler.getDistName(PathAssembler.java:84)
        at org.gradle.wrapper.PathAssembler.getDistribution(PathAssembler.java:40)
        at org.gradle.wrapper.Install.createDist(Install.java:44)

        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:107)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
(node:2388) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: cmd: Command failed with exit code 1 Error output:
Exception in thread "main" java.lang.NullPointerException
        at org.gradle.wrapper.PathAssembler.getDistName(PathAssembler.java:84)
        at org.gradle.wrapper.PathAssembler.getDistribution(PathAssembler.java:40)
        at org.gradle.wrapper.Install.createDist(Install.java:44)
        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:107)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
(node:2388) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

[OK] Your app has been deployed.
     Did you know you can live-reload changes from your app with --livereload?

Answer 4

DROP TABLE IF EXISTS #tmp_test01

CREATE TABLE #tmp_test01 ( [KEY]        INT
                         , Year_Month   INT
                         , Amount       INT
                         )

INSERT INTO #tmp_test01 
VALUES 
  (1, 201612, 100)  
, (1, 201701, 120)
, (2, 201605, 1000)
, (2, 201608, 800)
, (3, 201705, 500)


WITH CTE AS (

SELECT ROW_NUMBER() OVER (PARTITION BY [KEY]  ORDER BY [KEY], [Year_Month]) RN
     , [KEY]
     , Year_Month
     , Amount
FROM #tmp_test01

)

SELECT [KEY]
     , Year_Month
     , Amount
FROM CTE
WHERE RN = 1

选择键相同但某个属性最低的行

4 个答案: