差分及延3差分在MySQL数据库中实现

前提：comm延续

sal_1：差分

sal_2：延3差分

 

 

select u1.empno,u1.sal,u1.comm,u1.sal_1,u2.sal_2
from
(select t.empno,t.sal,t.comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_1
from test.emp t
order by comm) u1 LEFT JOIN
(select t.comm+3 as comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_2
from test.emp t
order by comm) u2
ON u1.comm = u2.comm;

 

在MySQL4.1中子查询是不能使用LIMIT的，手册中也明确指明 This version of MySQL doesn’t yet support ‘LIMIT & IN/ALL/ANY/SOME subquery’

也就是说，这样的语句是不能正确执行的。
select * from table where id in (select id from table limit 10);

但是，只要你再来一层就行。。如：
select * from table where id in (select t.id from (select * from table limit 10)as t)

 

select u1.empno,u1.sal,u1.comm,u1.sal_1,u2.sal_2
 from
 (select t.empno,t.sal,t.comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_1
 from test.emp t
 order by comm) u1 LEFT JOIN
 (select t.comm+3 as comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_2
 from test.emp t
 order by comm) u2
 ON u1.comm = u2.comm where
u1.empno not in (
select * from
(
select u.empno
from (
select u1.empno,u1.sal,u1.comm,u1.sal_1,u2.sal_2
 from
 (select t.empno,t.sal,t.comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_1
 from test.emp t
 order by comm) u1 LEFT JOIN
 (select t.comm+3 as comm,sal-(select sal from test.emp t2 where t2.comm +1 = t.comm order by comm) as sal_2
 from test.emp t
 order by comm) u2
 ON u1.comm = u2.comm) u limit 4) as t
 )

 

 

empno, sal, comm, sal_1, sal_2

999, 808, 80, ,
998, 885, 81, 77,
997, 807, 82, -78,
996, 804, 83, -3,
995, 855, 84, 51, 77
994, 888, 85, 33, -78
993, 856, 86, -32, -3