select top 1 * from T where guid='47D9E128-4174-4696-9C79-32343332BFEE' order by newid()
我在问一下 要是我抓出想抓出每一个id 怎么抓出来呢 是套放在变量中的 例如: guid id 47D9E128-4174-4696-9C79-32343332BFEE 001 47D9E128-4174-4696-9C79-32343332BFEE 002 47D9E128-4174-4696-9C79-32343332BFEE 003 47D9E128-4174-4696-9C79-32343332BFEE 004 47D9E128-4174-4696-9C79-32343332BFEE 005 DECLARE @M NVARCHAR(32) declare @N nvarchar(32) SELECT @m=ID From tablename where Guid=@guid select @n=ID from tablename where GUid=@guid
declare @T table( guid uniqueidentifier, id char(3), name varchar(2)) insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','001','a' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','002','b' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','003','c' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','004','d' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','005','e' insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','006','d' --F增加两条记录 insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','007','e'--Fselect * from @T t where ID=(select top 1 ID from @t where t.guid=guid order by newID()) /* guid id name ------------------------------------ ---- ---- 47D9E128-4174-4696-9C79-32343332BFEE 004 d 47D9E128-4174-4696-9C79-32343332BFEF 006 d(所影响的行数为 2 行) */
直接用select外层表有多条记录,容易造成不准确:用表变量/临时表存储结果集:declare @T table( guid uniqueidentifier, id char(3), name varchar(2)) insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','001','a' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','002','b' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','003','c' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','004','d' insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','005','e' insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','006','d' insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','007','e' insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','005','e' insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','006','d' insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','007','e' declare @T2 table( guid uniqueidentifier, id char(3), name varchar(2))--用表变量存储结果集declare test cursor for select guid from @T group by guid declare @guid uniqueidentifier open test fetch next from test into @guid while @@fetch_status=0 begin insert @T2 select top 1 * from @T where guid=@guid order by newID() fetch next from test into @guid end close test deallocate testselect * from @T2/*guid id name ------------------------------------ ---- ---- 47D9E128-4174-4696-9C11-32343332BFEA 006 d 47D9E128-4174-4696-9C79-32343332BFEE 002 b 47D9E128-4174-4696-9C79-32343332BFEF 007 e(所影响的行数为 3 行)*/
--按某一字段分组取最大(小)值所在行的数据(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 */
select a.* from tb a where id = (select top 1 id from tb where guid = a.guid order by newid()) order by a.guid
select top 1 *
from T
where guid='47D9E128-4174-4696-9C79-32343332BFEE'
order by newid()
例如: guid id
47D9E128-4174-4696-9C79-32343332BFEE 001
47D9E128-4174-4696-9C79-32343332BFEE 002
47D9E128-4174-4696-9C79-32343332BFEE 003
47D9E128-4174-4696-9C79-32343332BFEE 004
47D9E128-4174-4696-9C79-32343332BFEE 005 DECLARE @M NVARCHAR(32)
declare @N nvarchar(32) SELECT @m=ID From tablename where Guid=@guid
select @n=ID from tablename where GUid=@guid
declare @T table( guid uniqueidentifier, id char(3), name varchar(2))
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','001','a'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','002','b'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','003','c'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','004','d'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','005','e'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','006','d' --F增加两条记录
insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','007','e'--Fselect * from @T t where ID=(select top 1 ID from @t where t.guid=guid order by newID())
/*
guid id name
------------------------------------ ---- ----
47D9E128-4174-4696-9C79-32343332BFEE 004 d
47D9E128-4174-4696-9C79-32343332BFEF 006 d(所影响的行数为 2 行)
*/
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','001','a'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','002','b'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','003','c'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','004','d'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEE','005','e'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','006','d'
insert @T select '47D9E128-4174-4696-9C79-32343332BFEF','007','e'
insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','005','e'
insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','006','d'
insert @T select '47D9E128-4174-4696-9C11-32343332BFEA','007','e'
declare @T2 table( guid uniqueidentifier, id char(3), name varchar(2))--用表变量存储结果集declare test cursor for
select guid from @T group by guid
declare @guid uniqueidentifier
open test
fetch next from test into @guid
while @@fetch_status=0
begin
insert @T2
select top 1 * from @T where guid=@guid order by newID()
fetch next from test into @guid
end
close test
deallocate testselect * from @T2/*guid id name
------------------------------------ ---- ----
47D9E128-4174-4696-9C11-32343332BFEA 006 d
47D9E128-4174-4696-9C79-32343332BFEE 002 b
47D9E128-4174-4696-9C79-32343332BFEF 007 e(所影响的行数为 3 行)*/
/*
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
*/