mysql累加、累减

2022-10-11,

累加

先上表结构:

create table `abc` (
  `jidu` int(11) not null auto_increment,
  `jine` int(11) default null,
  primary key (`jidu`)
) engine=innodb auto_increment=14270 default charset=utf8;

数据:

insert into `abc` (`jidu`, `jine`) values ('1', '100');
insert into `abc` (`jidu`, `jine`) values ('2', '200');
insert into `abc` (`jidu`, `jine`) values ('3', '300');
insert into `abc` (`jidu`, `jine`) values ('4', '300');

想要的结果为季度金额的累加值:

 

 

 

这里利用错位自关联来实现,先看关联效果

select * from abc a join abc b on a.jidu >= b.jidu;

 

 

 下面就好办了,实现语句为:

select a.jidu,a.jine,sum(b.jine) as leiji
from abc a join abc b on a.jidu >= b.jidu 
group by a.jidu order by jidu;

 

累减

还是上面那个表,要的结果为每季度的金额差额:

 

 

 还是自关联,先看关联效果:

select * from abc a left join abc b on a.jidu = b.jidu+1 order by a.jidu;

 

 实现的sql:

select a.jidu,a.jine,ifnull(a.jine-b.jine,a.jine) as cha 
from abc a left join abc b on a.jidu = b.jidu+1 order by a.jidu;

完事,如有不对的地方请指正。

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