Mysql子查询

Question

我需要帮助来编写子查询。

我有一个包含精选文章和非精选文章的类别的文章表。

我想挑选4个最新的精选文章，这些精选文章不属于前6个最新的精选文章，无论其类别如何。这是我做了什么

select title 
from node 
where nid NOT IN(select nid from node order by date limit 6) 
order by date 
limit 4 

Answer 1

假设了一下这里，但你的意思是这样的吗？

select title 
from node 
where nid NOT IN(select nid from node where featured = 1 order by date desc limit 6) 
and featured = 1 
and category = ... 
order by date desc 
limit 4 

Answer 2

我记得，LIMIT尚不支持在IN()子查询。相反，您需要针对子查询LEFT JOIN并在子查询中查找NULL s：

SELECT title 
FROM 
    node 
    LEFT JOIN (SELECT nid FROM node ORDER BY date LIMIT 6) nids ON node.nid = nids.nid 
WHERE 
    nids.nid IS NULL 
    AND node.category = 'some category' 
ORDER BY date 
LIMIT 4