Php 此sql语句引发错误

我尝试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，在那里我可以做这个

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

但是查询抛出了一个错误

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

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

---

删除

课程。

从顶部的“已发布、存档和草稿”前面删除。@IanSellar仍然是相同的错误您在将它们与组合时，从内部查询中只返回一列（三行）UNION@davek我怎样才能实现我所描述的？如果你愿意，考虑以下简单的两步行动：1。如果您还没有这样做，请提供适当的DDL（和/或SQLFIDLE），以便我们可以更轻松地复制问题。2.如果尚未这样做，请提供与步骤1中提供的信息相对应的所需结果集。