android - 如何在 Android 2.1 中使用 select in join 子句？

Question

我有一个查询执行一些神奇的排序组连接，它在 Android 2.2 (froyo) 版本的 SQLite 上工作得很好:

SELECT channels.*, p.*
FROM channels 
LEFT JOIN programs p ON channels._id = p.channel_id
JOIN (select p2.channel_id, max(p2.airdate) max_air FROM programs p2 
      GROUP BY p2.channel_id) pj
ON pj.channel_id = p.channel_id AND pj.max_air = p.airdate
ORDER BY channels.channel_index asc;

出于某种原因，加入不适用于 Android 2.1，但失败了

no such column: pj.channel_id

我认为这是因为 SQLite 已从 2.1 升级到 2.2，但是适用于这两个版本的正确 SQL 是什么？

Answer 1

解决方案很简单，我只需要删除别名“p”:

SELECT channels.*, programs.*
FROM channels
LEFT JOIN programs ON channels._id = programs.channel_id
JOIN (select p2.channel_id channel_id, max(p2.airdate) max_air FROM programs p2
      GROUP BY p2.channel_id) pj
ON pj.channel_id = programs.channel_id AND pj.max_air = programs.airdate