SQL语句积累

1. 获得某一栏位有重复的记录：
declare @tab table(number1 int,number2 int,content varchar(20))
insert @tab values(2,3,'abc')
insert @tab values(2,4,'bb')
insert @tab values(2,5,'abc')
insert @tab values(3,6,'ccc')
insert @tab values(3,7,'ccc')
insert @tab values(6,3,'dd')
select * from @tab where content in(select content from @tab group by content having count(content)>1)
select distinct * from @tab t where (select count(content) from @tab where t.content=content)>1
2. 按拼音排序
select * from titles order by type collate Chinese_PRC_CS_AS_KS_WS
3. @@rowcount 表中记录数量
4. 每个分组中第二大的值
declare @t table (N int ,W bit)
insert into @t select 2005001,0
union all select 2005002,0
union all select 2005003,0
union all select 2005200,1
union all select 2005201,1
union all select 2005202,1
select * from @t where n in (select max(N) as N from @t where N not in (select max(n) as N from @t group by w ) group by w)
5.
create table a
(编码varchar(20),名称varchar(20),数量int,日期varchar(20))
create table b
(编码varchar(20),名称varchar(20),数量int,日期varchar(20))
create table c
(编码varchar(20),名称varchar(20),数量int,日期varchar(20))

insert a
select '001','aa',100,'1-1' union all
select '002','bb',20,'1-1'

insert b
select '001','aa',100,'1-20' union all
select '002','bb',110,'1-1' union all
select '003','cc',10,'1-4'

insert c
select '001','aa',100,'1-1'

select * from a
inner join b on a.编码=b.编码
select * from a
left join b on a.编码=b.编码
select * from a
full join b on a.编码=b.编码
select
isnull(a.编码,isnull(b.编码,c.编码)) as 编码
,isnull(a.名称,isnull(b.名称,c.名称)) as 名称
,isnull(a.数量,0) as a数量
,isnull(b.数量,0) as b数量
,isnull(c.数量,0) as c数量

from a
full join b on a.编码=b.编码
full join c on a.编码=c.编码

drop table a
drop table b
drop table c
6.
declare @t table (tid int)
insert into @t select 1
insert into @t select 2
insert into @t select 3
insert into @t select 4
insert into @t select 5
insert into @t select 7
insert into @t select 9
insert into @t select 10
select min(tid) as tid from (select tid+1 as tid from @t where tid+1 not in (select * from @t)) t

declare @tid int
select @tid = min(tid) from @t

while exists(select 1 from @t where tid = @tid)
begin
set @tid = @tid + 1
end

select @tid
-----------------------------------------------
select min(t.a) from (select tid+1 a from @t t where not exists(select 1 from @t where tid = t.tid+1)) t