我有这张桌子:
select a.id, a.title, a.link, a.mclass, b.myids
from menu a
left outer join ( select parent, GROUP_CONCAT(id SEPARATOR ',') as myids
from menu
where parent = id
group by parent) b ON a.id = b.parent
where a.parent='0' and mid='horizontal'
我对特殊ID的内部选择是这样的:
select parent, GROUP_CONCAT(id SEPARATOR ',') as myids
from menu
where parent = '256'
无法得到这个结果
您可以对表和聚合进行自连接:
SELECT m1.id, m1.title, m1.link, m1.mclass,
GROUP_CONCAT(m2.id) myids
FROM menu m1 LEFT JOIN menu m2
ON m2.parent = m1.id
WHERE m1.parent = '0' AND m1.mid = 'horizontal'
GROUP BY m1.id, m1.title, m1.link, m1.mclass
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我来说两句