表一张
日期,名称,数值 3个字段 查询目的是,比如:看看5月的数值减去4月的数值是多少
查询结果:
名称········5月的值···4月的值····相减结果
名称b````````````···5······3·······2
名称c````````````···8······3·······5
名称a````````````···5······5·······0
名称d````````````···4······10······-6
名称F````````````···10·····20······-10
这样的SQL 已经写好了,但是现在希望查询结果再加一个字段
这个字段是将相减结果正的做综合,负的做综合
大体希望输出的的结果:
名称········5月的值···4月的值····相减结果·····正负综合
名称b````````````···5······3·······2········7
名称c````````````···8······3·······5········7
名称a````````````···5······5·······0········0
名称d````````````···4······10······-6········-16
名称F````````````···10·····20······-10```````````````-16
日期,名称,数值 3个字段 查询目的是,比如:看看5月的数值减去4月的数值是多少
查询结果:
名称········5月的值···4月的值····相减结果
名称b````````````···5······3·······2
名称c````````````···8······3·······5
名称a````````````···5······5·······0
名称d````````````···4······10······-6
名称F````````````···10·····20······-10
这样的SQL 已经写好了,但是现在希望查询结果再加一个字段
这个字段是将相减结果正的做综合,负的做综合
大体希望输出的的结果:
名称········5月的值···4月的值····相减结果·····正负综合
名称b````````````···5······3·······2········7
名称c````````````···8······3·······5········7
名称a````````````···5······5·······0········0
名称d````````````···4······10······-6········-16
名称F````````````···10·····20······-10```````````````-16
建议你列出你的表结构,并提供测试数据以及基于这些测试数据的所对应正确结果。
参考一下这个贴子的提问方式http://topic.csdn.net/u/20091130/20/8343ee6a-417c-4c2d-9415-fa46604a00cf.html
1. 你的 create table xxx .. 语句
2. 你的 insert into xxx ... 语句
3. 结果是什么样,(并给以简单的算法描述)
4. 你用的数据库名称和版本(经常有人在MS SQL server版问 MySQL)
这样想帮你的人可以直接搭建和你相同的环境,并在给出方案前进行测试,避免文字描述理解上的误差。