此sql语句引发错误

Question

我试图使用以下查询从表中获取计数数据

SELECT courses.published, courses.archived, courses.draft from
 (  select count(*) as published from courses where published = 't' union all
    select count(*) as draft from courses where draft = 't' union all
    select count(*) as archived from courses where archived = 't'
 ) as courses

我想要一张桌子，我可以做到这一点

$result['courses']['published']
$result['courses']['draft']
$result['courses']['archived']

但查询引发了错误

#1054 - Unknown column 'courses.archived' in 'field list'

Answer 1

这个怎么样：

select p.published, d.draft, a.archived
from
( select count(*) as published from courses where published = 't' ) p
cross join
( select count(*) as draft from courses where draft = 't' ) d
cross join 
( select count(*) as archived from courses where archived = 't' ) a