求一SQL語句，謝謝先拉

[hycheng163]

create table #t (kk varchar(10),hh varchar(10),ll int)
insert into #t select 'aa','bb',2
insert into #t select 'aa',null,3
insert into #t select 'ff','gg',5
insert into #t select 'ff',null,4
insert into #t select 'tt',null,10
insert into #t select 'oo',null,9
結果：
aa | bb | 2
ff | gg | 5
oo | null | 9
tt | null | 10
比較簡練，快速的語句

[playwarcraft]

create table #t (kk varchar(10),hh varchar(10),ll int) 
insert into #t select 'aa','bb',2 
insert into #t select 'aa',null,3 
insert into #t select 'ff','gg',5 
insert into #t select 'ff',null,4 
insert into #t select 'tt',null,10 
insert into #t select 'oo',null,9 

go
select a.*
from #t a
 inner join 
(select kk,max(hh) as hh
from #t
group by kk) b
on a.kk=b.kk and isnull(a.hh,'#$')=isnull(b.hh,'#$')

/*
aa	bb	2
ff	gg	5
oo	NULL	9
tt	NULL	10

*/
GO
drop table #t

[moonshineidolon]

没看到规则呢

[百年树人]

select 
  kk+'|'+case when hh is null then 'null' else hh end+'|'+ltrim(ll) 
from #t

[hycheng163]

--改了一下：
create table #t (kk varchar(10),hh varchar(10),ll int)
insert into #t select 'aa','bb',2
insert into #t select 'aa',null,3
insert into #t select 'ff','gg',5
insert into #t select 'ff',null,4
insert into #t select 'tt',null,10
insert into #t select 'oo','jj',9

/*
結果
aa | bb | 2
ff | gg | 5
oo | jj | 9
tt | NULL| 10
*/

[百年树人]

select 
  kk+' | '+case when hh is null then 'null' else hh end+' | '+ltrim(ll) 
from #t

/**

-------------------------------------- 
aa | bb | 2
aa | null | 3
ff | gg | 5
ff | null | 4
tt | null | 10
oo | null | 9

（所影响的行数为 6 行）
**/

[dawugui]

create table #t (kk varchar(10),hh varchar(10),ll int) 
insert into #t select 'aa','bb',2 
insert into #t select 'aa',null,3 
insert into #t select 'ff','gg',5 
insert into #t select 'ff',null,4 
insert into #t select 'tt',null,10 
insert into #t select 'oo',null,9 
go

select t.* from #t t where hh = (select max(hh) from #t where kk = t.kk)
union all
select t.* from #t t where hh is null and kk not in (select t.kk from #t t where hh = (select max(hh) from #t where kk = t.kk))
order by kk

drop table #t

/*
kk         hh         ll          
---------- ---------- ----------- 
aa         bb         2
ff         gg         5
oo         NULL       9
tt         NULL       10

（所影响的行数为 4 行）
*/

[水族杰纶]

create table #t (kk varchar(10),hh varchar(10),ll int) 
insert into #t select 'aa','bb',2 
insert into #t select 'aa',null,3 
insert into #t select 'ff','gg',5 
insert into #t select 'ff',null,4 
insert into #t select 'tt',null,10 
insert into #t select 'oo',null,9 
select * from #t t where not exists(select 1 from #t where kk=t.kk and ll<t.ll)
drop table #T
/*kk         hh         ll          
---------- ---------- ----------- 
aa         bb         2
ff         NULL       4
tt         NULL       10
oo         NULL       9

(影響 4 個資料列)*/

[htl258_Tony]

select * from #t a where ll in(select max(ll) from #t where kk=a.kk)

[htl258_Tony]

create table #t (kk varchar(10),hh varchar(10),ll int) 
insert into #t select 'aa','bb',2 
insert into #t select 'aa',null,3 
insert into #t select 'ff','gg',5 
insert into #t select 'ff',null,4 
insert into #t select 'tt',null,10 
insert into #t select 'oo',null,9 
select * from #t a where ll in(select min(ll) from #t where kk=a.kk)
drop table #T

kk         hh         ll          
---------- ---------- ----------- 
aa         bb         2
ff         NULL       4
oo         NULL       9
tt         NULL       10

（所影响的行数为 4 行）

[htl258_Tony]

误解了

[没什么是无所不能的]

select kk+' | '+isnull(hh,'null')+' | '+cast(ll as varchar(10))
from ( select kk, hh, ll, row_number() over(partition by kk order by hh desc) rn from t) a
where a.rn = 1