SQL Server 按某一字段分组 取 最大 (小)值所在行的数据 -- 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 memoa 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 b2b2b2b2b 4 b4b4b 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.valselect 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.valselect 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*/ |
SQL按字段分组取最大(小)值记录（重复记录）,布布扣,bubuko.com
原文：http://www.cnblogs.com/drinkoJam/p/3807355.html