每个派生的表必须有它自己的别名

Question

我有以下查询：

SELECT `snap`.`ID`, `user`.`username`, `vote`.`type` 
FROM (`snap`) JOIN `user` as u ON `u`.`ID` = `snap`.`user` 
LEFT JOIN (select * from vote where user = "18") as vote ON `snap`.`ID` = `vote`.`snap` 
JOIN (SELECT CEIL(MAX(ID)*RAND()) AS ID FROM snap)) AS x ON `snap`.`ID` => `x`.`ID` 
WHERE `snap`.`active` = 0 LIMIT 1 

它工作得很好，直到我添加的最后一个加入。现在我得到错误：“每个派生表必须有它自己的别名”。我知道这是因为每个表都需要它的别名，我需要把“as S”或某处放在某处，但我无法知道如何在此查询中执行此操作。

Answer 1

看起来像你有一个额外的右括弧后。它应该是1而不是2个括号。

SELECT `snap`.`ID`, `user`.`username`, `vote`.`type` 
FROM (`snap`) JOIN `user` as u ON `u`.`ID` = `snap`.`user` 
LEFT JOIN (select * from vote where user = "18") as vote ON `snap`.`ID` = `vote`.`snap` 
JOIN (SELECT CEIL(MAX(ID)*RAND()) AS ID FROM snap) AS x ON `snap`.`ID` = `x`.`ID` 
WHERE `snap`.`active` = 0 LIMIT 1 

Answer 2

正确的语法是：

SELECT `snap`.`ID`, `user`.`username`, `vote`.`type` 
FROM (`snap`) JOIN `user` as u ON `u`.`ID` = `snap`.`user` 
LEFT JOIN (select * from vote where user = "18") as vote ON `snap`.`ID` = `vote`.`snap` 
JOIN (SELECT CEIL(MAX(ID)*RAND()) AS ID FROM snap) AS x ON `snap`.`ID` = `x`.`ID` 
WHERE `snap`.`active` = 0 LIMIT 1