Question

我有这三张桌子。

频道（id，id_account，kind，datetime，state，id_target）
channel_contacts（id，id_channel，id_contact，archived）
channel_events（id，id_channel_contacts，code，details，datetime）

channel_contacts与频道的关系

PRIMARY KEY (`id`),
UNIQUE INDEX `CONTRAINT` (`id_channel`, `id_contact`),
INDEX `idx_channel_contact_archived` (`archived`),
INDEX `channel_contacts_ibfk_2` (`id_contact`),
CONSTRAINT `channel_contacts_ibfk_1` FOREIGN KEY (`id_channel`) REFERENCES `channels` (`id`) ON DELETE CASCADE,
CONSTRAINT `channel_contacts_ibfk_2` FOREIGN KEY (`id_contact`) REFERENCES `contact` (`id_contact`) ON DELETE SET NULL

channel_events与channel_contacts的关系

PRIMARY KEY (`id`),
INDEX `id_channel_contacts` (`id_channel_contacts`),
CONSTRAINT `channel_events_ibfk_1` FOREIGN KEY (`id_channel_contacts`) REFERENCES `channel_contacts` (`id`) ON DELETE CASCADE

可以看出它们是相关的。

我希望来自channels_events表的所有那些属于通道表中id_account 123的事件。

我写了以下查询，它给了我以下

的问题

未知栏＆＃39; channel_contacts.id_channel＆＃39;在＆＃39; on条款＆＃39;

SELECT channels.id, channels.kind, channels.publish_date,
  channel_contacts.id_channel, channel_contacts.id_contact,
  channel_contacts.archived, channel_events.id,
  channel_events.id_channel_contacts, channel_events.code,
  channel_events.details, channel_events.occation
FROM channel_events
JOIN channels
  ON channels.id = channel_contacts.id_channel
JOIN channel_contacts
  ON channel_contacts.id_contact = channel_events.id_channel_contacts
where channels.id_account = 123;

Answer 1

我认为这是一个错字，您已经在频道联系人之前将频道表加入了频道表，因此尚未识别channels_contanct。试试这个：

SELECT channels.id, channels.kind, channels.publish_date, channel_contacts.id_channel, channel_contacts.id_contact, channel_contacts.archived, channel_events.id, channel_events.id_channel_contacts, channel_events.code, channel_events.details, channel_events.occation
FROM channel_events 
JOIN channel_contacts ON channel_contacts.id= channel_events.id_channel_contacts
JOIN channels ON channels.id = channel_contacts.id_channel
where channels.id_account = 123;

如何为一对多映射记录编写查询

1 个答案: