Question

我想获得每个GV（TeacherID）的第一行

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

帮助我。

Answer 1

编辑：好的，现在你已经编辑了这个问题，这个答案看起来完全不相关......叹息......我会留下它以防万一它可以帮助你开始。欢呼声。

根据您的规格提供最简单的解决方案：

  select teacherid 
    from mytable 
group by teacherid;

除了teacherid：

之外，还需要其他信息

  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;

警告：我没有安装SQL-Server进行测试，因此语法可能不完全正确;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

<强> DDL

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

示例记录

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)

<强>查询

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

<强>结果集

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

获得一组的第一行

3 个答案: