獲取第一排爲一組

Question

我想要得到的第一排，每GV（TeacherID）

GV | Class| SUM 
GV1| L001 | 5000 
GV1| L002 | 5000 
GV1| L003 | 5000 
GV2| L002 | 7000 
GV2| L003 | 7000 
GV2| L001 | 7000 
GV3| L001 | 8000 
GV3| L002 | 8000 
GV3| L003 | 8000 

幫助我。

Answer 1

編輯：好吧，現在你已經編輯了這個問題，使這個答案看起來完全不相關...嘆...我會離開它，以防它可以幫助你開始。乾杯。

---

最簡單的解決方案給您的規格：

select teacherid 
    from mytable 
group by teacherid; 

如果您需要在除了teacherid其他信息：

select teacherid, ...other cols... 
    from (select teacherid, ...other cols... 
       row_number() over (
        partition by teacherid 
        order by classid /* or class as per edit */) as row_num 
      from mytable) my_derived_table 
    where my_derived_table.row_num = 1; 

買者自負：我沒有的安裝SQL-Server方便測試，因此語法可能不完全正確;但它很接近。

Answer 2

WITH T AS (
    SELECT yourTable.*, ROW_NUMBER() OVER(PARTITION BY TeacherID 
     ORDER BY ClassID) AS RN 
    FROM yourTable 
) 
SELECT * 
FROM T 
WHERE RN = 1 

Answer 3

DDL

create table #t 
(
    GV varchar(4), 
    Class varchar(4), 
    [SUM] int 
) 

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樣本記錄

insert into #t(GV, Class, [SUM])values('GV1', 'L001', 5000) 
insert into #t(GV, Class, [SUM])values('GV1', 'L002', 5000) 
insert into #t(GV, Class, [SUM])values('GV1', 'L003', 5000) 
insert into #t(GV, Class, [SUM])values('GV2', 'L002', 7000) 
insert into #t(GV, Class, [SUM])values('GV2', 'L003', 7000) 
insert into #t(GV, Class, [SUM])values('GV2', 'L001', 7000) 
insert into #t(GV, Class, [SUM])values('GV3', 'L001', 8000) 
insert into #t(GV, Class, [SUM])values('GV3', 'L002', 8000) 
insert into #t(GV, Class, [SUM])values('GV3', 'L003', 8000) 

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查詢

Select GV, class, [sum] from 
(
    Select Row_Number() Over(Partition by GV Order by GV) as RowId, * from #t 
)K 
Where RowId = 1 

drop table #t 

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結果集

GV class sum 
---- ----- ---- 
GV1 L001 5000 
GV2 L002 7000 
GV3 L001 8000