Mysql:如何用if else条件查询if

Question

我在查询数据时遇到麻烦.我不知道从哪里开始查询if else condition if inside if.

问题是:如何查询其类型= cpm和end_date <now()然后将结果值类型更改为之前,如果其类型= cpm和end_date> now(),则将结果值类型更改为after.我在表中有数据,结果如下:

我想得到如下结果:

Array(
  [0] => Array
        (
            [id] => 1
            [type] => free
            [end_date] => 2013-06-20
        )
  [1] => Array
        (
            [id] => 4
            [type] => after
            [end_date] => 2013-08-29
        )
  [2] => Array
        (
            [id] => 5
            [type] => before
            [end_date] => 2013-06-20
        )
)

提前致谢.

Answer 1

这样的事情应该有效:

select 
  id, 
  case 
    when (type = 'cpm' and end_date < now()) then 'before' 
    when (type = 'cpm' and end_date > now()) then 'after' 
    else type
  end as type, 
  end_date
from my_table;