sql - SQL查询不排序描述

Question

此 sql 命令在 sqlitemanager 中运行良好，但在我的 android 应用程序中，这不排序 desc ...

select t._id,  u.name, c.commdate, c.message
from tickets t, users u, comments c
where c.userid = u._id and c.ticketid = t._id
and t.status = 5
group by t._id
having max(c.commdate)
order by c.commdate desc

Answer 1

我觉得“拥有”部分是个问题。尝试（未经测试）；

SELECT t._id, u.name, c.commdate, c.message
FROM tickets t
JOIN comments c ON (t._id = c.ticketid)
-- Find most decent comments on tickets, but handle lack of any comments
LEFT JOIN (
    SELECT c2.ticketid, MAX(c2.commdate) as max_commdate
    FROM comments c2
) AS latest ON (c.ticketid = latest.ticketid AND c.commdate = latest.max_commdate)
JOIN users u ON (c.userid = i._id)
WHERE t.status = 5
ORDER BY t._id DESC, c.commdate DESC