Mysql:多行比较

Question

来自这个 Mysql 表:

Attributes
Brand   |attr   |   vals
Samsung | RAM   |   '750'
Samsung | CPU   |   '1200'
HTC     | RAM   |   '1000'
HTC     | CPU   |   '1500'

我不知道如何获取所有项目

RAM>500
CPU>1300

作为结果，我只需要匹配所有参数的品牌:

Attributes
Brand   |attr   |   vals
HTC     | *     |   *

查看 SQL fiddle : http://sqlfiddle.com/#!2/491d7/1

Answer 1

我将通过旋转数据获得结果:

select brand, RAM, CPU
from
(
   select brand,
      max(case when attr='RAM' then cast(vals as unsigned) end) as RAM,
      max(case when attr='CPU' then cast(vals as unsigned) end) as CPU
   from attributes
   group by brand
) d
where RAM > 500
  and CPU > 1300

参见 SQL Fiddle with Demo