例 num time
1 11:12
1 13:14
2 11:04
19 个解决方案
#1
是不是有相同的NUM只取一个?
#2
select * from table where name in (select name from table group by name having count(*) = 1)
#3
1.select num,min(time) from TB group by num
2.select * from TB A where not exists(select 1 from TB where A.num=num And A.time<time)
#4
--取不存在两条以上的num的记录,即只有一条num的记录
select * from tb where not exists(select 1 from tb t where tb.num=t.num group by num having count(*)>1)
--取最小值
select * from tb where time=(select min(time) from tb t where tb.num=t.num )
#5
--如果只有这两字段
select num, max(time) time from tb group by num
select num, min(time) time from tb group by num
--如果不止这两字段,多个字段
select t.* from tb t where time = (select max(time) from tb where num = t.num)
select t.* from tb t where time = (select min(time) from tb where num = t.num)
select t.* from tb t where not exists (select 1 from tb where num = t.num and time > t.time)
select t.* from tb t where not exists (select 1 from tb where num = t.num and time < t.time)
#6
#7
任你挑
--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
--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
--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
--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
--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
--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
--七,如果整行数据有重复,所有的列都相同。
--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)
*/
#8
我是来学习的,受益匪浅
#9
路过,很好很强大
#10
-----
#11
#12
大乌龟最近很活跃啊。
#13
各种大神出手 学习
#14
#15
#16
#17
谢谢!学了一招~!
#18
select num, max(time) as time
from TB
group by num
having count(*)=1
或者
select b.*
from (select num from TB group by num having count(*) = 1) as a
join TB as b
on a.num = b.num
更通用一些,如果要找恰好有@n条记录的num对应的所有记录
with a as (
select num from TB group by num having count(*) = @n
)
select tb.*
from TB join a on a.num=tb.num
from TB
group by num
having count(*)=1
或者
select b.*
from (select num from TB group by num having count(*) = 1) as a
join TB as b
on a.num = b.num
更通用一些,如果要找恰好有@n条记录的num对应的所有记录
with a as (
select num from TB group by num having count(*) = @n
)
select tb.*
from TB join a on a.num=tb.num
#19
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#20
#1
是不是有相同的NUM只取一个?
#2
select * from table where name in (select name from table group by name having count(*) = 1)
#3
1.select num,min(time) from TB group by num
2.select * from TB A where not exists(select 1 from TB where A.num=num And A.time<time)
#4
--取不存在两条以上的num的记录,即只有一条num的记录
select * from tb where not exists(select 1 from tb t where tb.num=t.num group by num having count(*)>1)
--取最小值
select * from tb where time=(select min(time) from tb t where tb.num=t.num )
#5
--如果只有这两字段
select num, max(time) time from tb group by num
select num, min(time) time from tb group by num
--如果不止这两字段,多个字段
select t.* from tb t where time = (select max(time) from tb where num = t.num)
select t.* from tb t where time = (select min(time) from tb where num = t.num)
select t.* from tb t where not exists (select 1 from tb where num = t.num and time > t.time)
select t.* from tb t where not exists (select 1 from tb where num = t.num and time < t.time)
#6
#7
任你挑
--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
--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
--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
--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
--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
--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
--七,如果整行数据有重复,所有的列都相同。
--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)
*/
#8
我是来学习的,受益匪浅
#9
路过,很好很强大
#10
-----
#11
#12
大乌龟最近很活跃啊。
#13
各种大神出手 学习
#14
#15
#16
#17
谢谢!学了一招~!
#18
select num, max(time) as time
from TB
group by num
having count(*)=1
或者
select b.*
from (select num from TB group by num having count(*) = 1) as a
join TB as b
on a.num = b.num
更通用一些,如果要找恰好有@n条记录的num对应的所有记录
with a as (
select num from TB group by num having count(*) = @n
)
select tb.*
from TB join a on a.num=tb.num
from TB
group by num
having count(*)=1
或者
select b.*
from (select num from TB group by num having count(*) = 1) as a
join TB as b
on a.num = b.num
更通用一些,如果要找恰好有@n条记录的num对应的所有记录
with a as (
select num from TB group by num having count(*) = @n
)
select tb.*
from TB join a on a.num=tb.num
#19
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