这样的需求sql怎么写?-PHP Tutorial-php.cn

这样的需求sql怎么写?

WBOY

Release： 2016-06-20 12:42:51

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一个排序的sql
按status 字段倒序
如果status=1 time字段正序,如果status=0 time字段倒序

下面是需要出来的结果

id   status  time
5        1         50
6        1         51
1        0         99
10      0          1

回复讨论(解决方案)

select * from (select * from 表 where status = 1 order by time)aunion allselect * from (select * from 表 where status = o order by time desc)b

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select * from table order by status desc,if(status=1,'time asc','time desc');

order by time (case when status = 1 then desc else asc end)

select * from (select * from 表 where status = 1 order by time)aunion allselect * from (select * from 表 where status = o order by time desc)b

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不行的,我试过, order要起作用,后面必须要跟limit

select * from table order by status desc,if(status=1,'time asc','time desc');

这种写法也试过,无效的 if不能这么用

去试了没？
你用的什么数据库？

select * from table order by status desc,if(status=1,'time asc','time desc');

这种写法也试过,无效的 if不能这么用

select * from tbl_name order by status=1 desc, time*if(status=1,1,-1)

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其中
time*if(status=1,1,-1) 将 status=0 的 time 变成负数，以适应整体的升序排列
status=1 desc 将所有 status=1 的排在最前面

order by time (case when status = 1 then desc else asc end)

这样写直接报错了

改成 order by (case when status = 1 then 'time desc' else 'time asc' end)
测试不行,跟union 效果一样

select * from tbl_name order by status=1 desc, time*if(status=1,1,-1)

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其中
time*if(status=1,1,-1) 将 status=0 的 time 变成负数，以适应整体的升序排列
status=1 desc 将所有 status=1 的排在最前面

这只适用于它这个表

order by time (case when status = 1 then desc else asc end)

这样写直接报错了

改成 order by (case when status = 1 then 'time desc' else 'time asc' end)
测试不行,跟union 效果一样

select * from table order by status=1 desc, status=0 asc 简单粗暴实用

select * from tbl_name order by status=1 desc, time*if(status=1,1,-1)

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其中
time*if(status=1,1,-1) 将 status=0 的 time 变成负数，以适应整体的升序排列
status=1 desc 将所有 status=1 的排在最前面

这只适用于它这个表

这个有用,但IF查询所有行进行运算再对比效率有点低了,我曾经想写个函数(实现功能通if),后来还是决定多建个字段,计算后按这个字段desc
但这样缺少灵活性,如果有其他特殊排序可能还要建字段,然后就又把排序字段纵向切割出来了....(针对大数据量)

order by time (case when status = 1 then desc else asc end)

这样写直接报错了

改成 order by (case when status = 1 then 'time desc' else 'time asc' end)
测试不行,跟union 效果一样

select * from table order by status=1 desc, status=0 asc 简单粗暴实用

这句实现不了的...

select * from (select * from 表 where status = 1 order by time)aunion allselect * from (select * from 表 where status = o order by time desc)b

Copy after login

不行的,我试过, order要起作用,后面必须要跟limit

你是什么数据库？

SELECT * FROM (SELECT * FROM `table2` WHERE `status`=1 ORDER BY time ASC) aUNION ALLSELECT * FROM (SELECT * FROM `table2` WHERE `status`=0 ORDER BY time DESC) b

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我在mysql 5.6上运行是OK的

select * from (select * from 表 where status = 1 order by time)aunion allselect * from (select * from 表 where status = o order by time desc)b

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不行的,我试过, order要起作用,后面必须要跟limit

你是什么数据库？

SELECT * FROM (SELECT * FROM `table2` WHERE `status`=1 ORDER BY time ASC) aUNION ALLSELECT * FROM (SELECT * FROM `table2` WHERE `status`=0 ORDER BY time DESC) b

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我在mysql 5.6上运行是OK的

mysql 5.5.24