日期:2014-05-18  浏览次数:20508 次

求一查询SQL语句最大数据字段的ID
select LocalDay,CallerNum,TargetNum,TalkDuration,SessionID,Direction,StartTime,EndTime,SequenceID,IVRData from EXTERNAL_CDR.dbo.CDRMAIN where SequenceID=1 and SessionID in (select SessionID from (select max(TalkDuration),SessionID from EXTERNAL_CDR.dbo.CDRMAIN group by SessionID ))错误的语句

想实现的结果

主要是后面
(select SessionID from (select max(TalkDuration),SessionID from EXTERNAL_CDR.dbo.CDRMAIN group by SessionID ))
想查询出最大TalkDuration的SessionID求请教...

------解决方案--------------------

(select SessionID from (select max(TalkDuration),SessionID from EXTERNAL_CDR.dbo.CDRMAIN group by SessionID ) tab)


加一个表别名
------解决方案--------------------
select LocalDay,CallerNum,TargetNum,TalkDuration,SessionID,Direction,StartTime,EndTime,SequenceID,IVRData from EXTERNAL_CDR.dbo.CDRMAIN where SequenceID=1 and SessionID in (select SessionID from (select max(TalkDuration),SessionID from EXTERNAL_CDR.dbo.CDRMAIN group by SessionID ) as 别名)

--主意在使用表表达式作为被查询的输入表时必须取别名,否则会报错的
------解决方案--------------------
SQL code


select LocalDay,CallerNum,TargetNum,TalkDuration,SessionID,Direction,StartTime,EndTime,SequenceID,IVRData from EXTERNAL_CDR.dbo.CDRMAIN where SequenceID=1 and SessionID in 
(SELECT sessionid FROM EXTERNAL_CDR.dbo.CDRMAIN WHERE TalkDuration=(SELECT MAX(TalkDuration) FROM EXTERNAL_CDR.dbo.CDRMAIN))

------解决方案--------------------
其他相关内容参考如下:
SQL code

--按某一字段分组取最大(小)值所在行的数据
--(爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 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