有如下表
表t
字段1,字段2,字段3
1 201 aa
1 201 bb
1 200 cc
2 301 dd
2 301 ee
2 300 ff
3 401 gg
3 401 hh
3 400 ii
想得到如下结果,1 201 aa
2 301 dd
3 401 gg也就是说字段2有重复的话,只取一个,我用max()查,它却把重复的全列出来了,
以上请高手指点啊!
表t
字段1,字段2,字段3
1 201 aa
1 201 bb
1 200 cc
2 301 dd
2 301 ee
2 300 ff
3 401 gg
3 401 hh
3 400 ii
想得到如下结果,1 201 aa
2 301 dd
3 401 gg也就是说字段2有重复的话,只取一个,我用max()查,它却把重复的全列出来了,
以上请高手指点啊!
insert into t values(1 ,201 ,'aa')
insert into t values(1 ,201 ,'bb')
insert into t values(1 ,200 ,'cc')
insert into t values(2 ,301 ,'dd')
insert into t values(2 ,301 ,'ee')
insert into t values(2 ,300 ,'ff')
insert into t values(3 ,401 ,'gg')
insert into t values(3 ,401 ,'hh')
insert into t values(3 ,400 ,'ii')
goselect m.* from t m where not exists(select 1 from t where 字段1=m.字段1 and (字段2 > m.字段2 or (字段2 = m.字段2 and 字段3 < m.字段3))) order by m.字段1drop table t/*
字段1 字段2 字段3
----------- ----------- ----------
1 201 aa
2 301 dd
3 401 gg(所影响的行数为 3 行)*/
create table t(字段1 int,字段2 int,字段3 varchar(10))
insert into t values(1 ,201 ,'aa')
insert into t values(1 ,201 ,'bb')
insert into t values(1 ,200 ,'cc')
insert into t values(2 ,301 ,'dd')
insert into t values(2 ,301 ,'ee')
insert into t values(2 ,300 ,'ff')
insert into t values(3 ,401 ,'gg')
insert into t values(3 ,401 ,'hh')
insert into t values(3 ,400 ,'ii')
goselect m.* from t m where not exists(select 1 from t where 字段1=m.字段1 and (字段2 > m.字段2 or (字段2 = m.字段2 and 字段3 < m.字段3))) order by m.字段1/*
字段1 字段2 字段3
----------- ----------- ----------
1 201 aa
2 301 dd
3 401 gg(所影响的行数为 3 行)*/select 字段1,字段2,字段3 from
(
select m.* , px = (select count(1) from t where 字段1=m.字段1 and (字段2 > m.字段2 or (字段2 = m.字段2 and 字段3 < m.字段3))) + 1 from t m
) k where px = 1
order by 字段1
/*
字段1 字段2 字段3
----------- ----------- ----------
1 201 aa
2 301 dd
3 401 gg(所影响的行数为 3 行)*/
drop table t
--sql 2005
create table t(字段1 int,字段2 int,字段3 varchar(10))
insert into t values(1 ,201 ,'aa')
insert into t values(1 ,201 ,'bb')
insert into t values(1 ,200 ,'cc')
insert into t values(2 ,301 ,'dd')
insert into t values(2 ,301 ,'ee')
insert into t values(2 ,300 ,'ff')
insert into t values(3 ,401 ,'gg')
insert into t values(3 ,401 ,'hh')
insert into t values(3 ,400 ,'ii')
goselect m.* from t m where not exists(select 1 from t where 字段1=m.字段1 and (字段2 > m.字段2 or (字段2 = m.字段2 and 字段3 < m.字段3))) order by m.字段1/*
字段1 字段2 字段3
----------- ----------- ----------
1 201 aa
2 301 dd
3 401 gg(3 行受影响)*/select 字段1,字段2,字段3 from
(
select m.* , px = row_number() over(partition by 字段1 order by 字段2 desc , 字段3) from t m
) k where px = 1
order by 字段1
/*
字段1 字段2 字段3
----------- ----------- ----------
1 201 aa
2 301 dd
3 401 gg(3 行受影响)*/
drop table t
(
select
t.*, ROW_NUMBER() over (partition by c1 order by c2 desc, c3) od
from t
) tt
where od = 1