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求SQL语句 在线解决马上结贴

wang520d 2008-01-16 12:45:42
表test
表内容:
id state users dates
1 1 1 2007-1-11
1 2 1 2008-1-11
2 2 2 2008-1-11
3 4 2 2007-1-11
2 4 2 2008-2-11



1步:根据时间先后去掉相同ID的记录 (要接近现在时间的记录) 我要的结果:
id state users dates
1 2 1 2008-1-11
3 4 2 2007-1-11
2 4 2 2008-2-11
...全文
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dobear_0922 2008-01-16
create table test(id int, state int, users int, dates datetime)
insert test select 1, 1, 1, '2007-1-11'
union all select 1, 2, 1, '2008-1-11'
union all select 2, 2, 2, '2008-1-11'
union all select 3, 4, 2, '2007-1-11'
union all select 2, 4, 2, '2008-2-11'

select id, state, users, dates=convert(varchar(10),dates,120) from test
where not exists (select 1 from test t where id=test.id and dates>test.dates)
/*
id state users dates
----------- ----------- ----------- ----------
1 2 1 2008-01-11
3 4 2 2007-01-11
2 4 2 2008-02-11

(3 row(s) affected)
*/

drop table test
回复
-狙击手- 2008-01-16
declare @t table(id int,state int,users int,dates datetime)
insert @t select
1,1 , 1,'2007-1-11' union select
1, 2 , 1,'2008-1-11' union select
2 ,2 , 2,'2008-1-11' union select
3 ,4 , 2,'2007-1-11' union select
2 ,4 , 2,'2008-2-11'


delete t
from @t t
where exists(select 1 from @t where t.id = id and dates > t.dates)

select * from @t
/*

id state users dates
----------- ----------- ----------- ------------------------------------------------------
1 2 1 2008-01-11 00:00:00.000
2 4 2 2008-02-11 00:00:00.000
3 4 2 2007-01-11 00:00:00.000

(所影响的行数为 3 行)


*/
回复
pt1314917 2008-01-16

select * from test a
where not exists(select 1 from test where a.id = id and dates > a.dates)
或者:
select * from test a where dates in(select max(datea) from test where id=a.id)
回复
tim_spac 2008-01-16
select * from test a
where not exists (
select 1 from test b
where b.id=a.id
and b.dates>a.dates)
回复
-狙击手- 2008-01-16
declare @t table(id int,state int,users int,dates datetime)
insert @t select
1,1 , 1,'2007-1-11' union select
1, 2 , 1,'2008-1-11' union select
2 ,2 , 2,'2008-1-11' union select
3 ,4 , 2,'2007-1-11' union select
2 ,4 , 2,'2008-2-11'

select *
from @t t
where not exists(select 1 from @t where t.id = id and dates > t.dates)

/*

id state users dates
----------- ----------- ----------- ------------------------------------------------------
1 2 1 2008-01-11 00:00:00.000
2 4 2 2008-02-11 00:00:00.000
3 4 2 2007-01-11 00:00:00.000

(所影响的行数为 3 行)


*/
回复
liangCK 2008-01-16
--按某一字段分组取最大(小)值所在行的数据
(爱新觉罗.毓华 2007-10-23于浙江杭州)
/*
数据如下:
name val memo
a 2 a2(a的第二个值)
a 1 a1--a的第一个值
a 3 a3:a的第三个值
b 1 b1--b的第一个值
b 3 b3:b的第三个值
b 2 b2b2b2b2
b 4 b4b4
b 5 b5b5b5b5b5
*/
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
go

--一、按name分组取val最大的值所在行的数据。
--方法1:
select a.* from tb a where val = (select max(val) from tb where name = a.name) order by a.name
--方法2:
select a.* from tb a where not exists(select 1 from tb where name = a.name and val > a.val)
--方法3:
select a.* from tb a,(select name,max(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4:
select a.* from tb a inner join (select name , max(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name
/*
name val memo
---------- ----------- --------------------
a 3 a3:a的第三个值
b 5 b5b5b5b5b5
*/

--二、按name分组取val最小的值所在行的数据。
--方法1:
select a.* from tb a where val = (select min(val) from tb where name = a.name) order by a.name
--方法2:
select a.* from tb a where not exists(select 1 from tb where name = a.name and val < a.val)
--方法3:
select a.* from tb a,(select name,min(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4:
select a.* from tb a inner join (select name , min(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val < a.val) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值
*/

--三、按name分组取第一次出现的行所在的数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name) order by a.name
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
*/

--四、按name分组随机取一条数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name order by newid()) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 5 b5b5b5b5b5
*/

--五、按name分组取最小的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val < a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val < a.val having Count(*) < 2) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
b 2 b2b2b2b2
*/

--六、按name分组取最大的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val desc) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val > a.val having Count(*) < 2) order by a.name
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
a 3 a3:a的第三个值
b 4 b4b4
b 5 b5b5b5b5b5
*/
--七,如果整行数据有重复,所有的列都相同。
/*
数据如下:
name val memo
a 2 a2(a的第二个值)
a 1 a1--a的第一个值
a 1 a1--a的第一个值
a 3 a3:a的第三个值
a 3 a3:a的第三个值
b 1 b1--b的第一个值
b 3 b3:b的第三个值
b 2 b2b2b2b2
b 4 b4b4
b 5 b5b5b5b5b5
*/
--在sql server 2000中只能用一个临时表来解决,生成一个自增列,先对val取最大或最小,然后再通过自增列来取数据。
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
go

select * , px = identity(int,1,1) into tmp from tb

select m.name,m.val,m.memo from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) m where px = (select min(px) from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) n where n.name = m.name)

drop table tb,tmp

/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值

(2 行受影响)
*/
--在sql server 2005中可以使用row_number函数,不需要使用临时表。
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
go

select m.name,m.val,m.memo from
(
select * , px = row_number() over(order by name , val) from tb
) m where px = (select min(px) from
(
select * , px = row_number() over(order by name , val) from tb
) n where n.name = m.name)

drop table tb

/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值

(2 行受影响)
*/
回复
dobear_0922 2008-01-16
select *
from test t
where not exists(select 1 from test where t.id = id and dates > t.dates)
回复
ygghost 2008-01-16
delete from test where dates not in
(
select max(dates) from test group by id
)
回复
liangCK 2008-01-16
select a.* 
from test a,(select id,max(dates) dates from test group by id) b
where a.id=b.id and a.dates=b.dates
回复
ygghost 2008-01-16
delete from test where dates not in
(
Select max(dates) from test group by id
)
回复
-狙击手- 2008-01-16
select *
from test t
where not exists(select 1 from test where t.id = id and dates > t.dates)
回复
pengxuan 2008-01-16
学习
回复
kk19840210 2008-01-16

----最接近与当天的日期
declare @t table(id int,state int,users int,dates datetime)
insert @t select
1,1 , 1,'2007-1-11' union select
1, 2 , 1,'2008-1-11' union select
2 ,2 , 2,'2008-1-11' union select
3 ,4 , 2,'2007-1-11' union select
2 ,4 , 2,'2008-2-11'


SELECT * FROM @T a where not exists (select 1 from @t where id=a.id and abs(datediff(ss,dates,getdate()))<abs(datediff(ss,a.dates,getdate())))



id state users dates
----------- ----------- ----------- -----------------------
1 2 1 2008-01-11 00:00:00.000
2 2 2 2008-01-11 00:00:00.000
3 4 2 2007-01-11 00:00:00.000

(3 行受影响)
回复
威尔亨特 2008-01-16
select * from test where dates in (select id,max(dates) from test group by id)
回复
wang520d 2008-01-16
无语 速度太快了
马上结贴了
回复
dobear_0922 2008-01-16
2可以优化一下:
create table test(id int, state int, users int, dates datetime)
insert test select 1, 1, 1, '2007-1-11'
union all select 1, 2, 1, '2008-1-11'
union all select 2, 2, 2, '2008-1-11'
union all select 3, 4, 2, '2007-1-11'
union all select 2, 4, 2, '2008-2-11'


-- 1
select id, state, users, dates=convert(varchar(10),dates,120) from test
where not exists (select 1 from test t where id=test.id and dates>test.dates)
/*
id state users dates
----------- ----------- ----------- ----------
1 2 1 2008-01-11
3 4 2 2007-01-11
2 4 2 2008-02-11

(3 row(s) affected)
*/

--2
select state, users, 状态出现的次数=count(1)
from test
where not exists (select 1 from test t where id=test.id and dates>test.dates)
group by state, users
/*
state users 状态出现的次数
----------- ----------- -----------
2 1 1
4 2 2

(2 row(s) affected)
*/

drop table test
回复
dobear_0922 2008-01-16
create table test(id int, state int, users int, dates datetime)
insert test select 1, 1, 1, '2007-1-11'
union all select 1, 2, 1, '2008-1-11'
union all select 2, 2, 2, '2008-1-11'
union all select 3, 4, 2, '2007-1-11'
union all select 2, 4, 2, '2008-2-11'


-- 1
select id, state, users, dates=convert(varchar(10),dates,120) from test
where not exists (select 1 from test t where id=test.id and dates>test.dates)
/*
id state users dates
----------- ----------- ----------- ----------
1 2 1 2008-01-11
3 4 2 2007-01-11
2 4 2 2008-02-11

(3 row(s) affected)
*/

--2
select state, users, 状态出现的次数=count(1)
from
(
select id, state, users, dates=convert(varchar(10),dates,120) from test
where not exists (select 1 from test t where id=test.id and dates>test.dates)
) T group by state, users
/*
state users 状态出现的次数
----------- ----------- -----------
2 1 1
4 2 2

(2 row(s) affected)
*/

drop table test
回复
utpcb 2008-01-16
UP
回复
liangCK 2008-01-16
select state,users,count(state)
from tb
group by state,users
回复
wang520d 2008-01-16
2步 : 根据USERS 去统计 每一个USERS 对应的 STATE 出现的次数。。

id state users dates
----------- ----------- ----------- ------------------------------------------------------
1 2 1 2008-01-11 00:00:00.000
2 4 2 2008-02-11 00:00:00.000
3 4 2 2007-01-11 00:00:00.000


要求结果

state users 状态出现的次数
----------- ----------- ----------- ------------------------------------------------------
2 1 1 --(用户1下状态2出现了1次)
4 2 2 --(用户2下状态4出现2次)




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