从另一个表 SQL 的值更新列值

Question

我有一个表 chatmessages，它有一个 chatId、incomingId、goingId 列，我还有另一个表 chatmembers，它有一个 chatId、usersId 列。还有另一个表chat，它只包含chatId，以及聊天的usersId 初始化程序，即user1

现在，我想将chatId从chatmembers复制到chatmessages，其中有相同的用户，例如incomingId 83和outingId 81在chatmembers中具有相同的chatId

我有这个查询，但它不起作用

UPDATE chatmessages SET chatId = 
(SELECT c.chatId FROM chat AS c INNER JOIN (SELECT chatId FROM chatmembers WHERE usersId = incomingId) AS uc ON c.chatId = uc.chatId 
INNER JOIN (SELECT chatId FROM chatmembers WHERE companyId = outgoingId) AS cc ON uc.chatId = cc.chatId)

Answer 1

你必须把这个查询写在数组中，然后执行， 也可以在

中使用双引号

(SELECT c.chatId FROM chat AS c 
INNER JOIN (SELECT chatId FROM chatmembers WHERE usersId = incomingId) AS uc ON c.chatId = uc.chatId 
INNER JOIN (SELECT chatId FROM chatmembers WHERE companyId = outgoingId)

喜欢这个

("SELECT c.chatId FROM chat AS c 
INNER JOIN (SELECT chatId FROM chatmembers WHERE usersId = incomingId) AS uc ON c.chatId = uc.chatId 
INNER JOIN (SELECT chatId FROM chatmembers WHERE companyId = outgoingId") 

Answer 2

如果我理解正确，您可以使用joins。以下使用 MySQL 语法：

update chatmessages cm join
       chatusers cuo
       on cuo.userid = cm.outgoingid join
       chatusers cui
       on cui.userid = cm.incomingid and
          cui.chatid = cuo.chatid
   set cm.chatid = cuo.chatid;