这个mysql查询有什么问题？

Question

SELECT app_contracts.*, app_customers.id as customer, app_boards.id as board
 WHERE app_customers.id=app_contracts.customer_id 
 AND app_boards.id=app_contracts.board_id 
 ORDER BY app_contracts.id DESC

错误：

  

错误号码：1064

     

您的SQL语法有错误;   检查对应的手册   您的MySQL服务器版本   正确的语法在'WHERE附近使用   app_customers.id = app_contracts.customer_id   AND app_boards.id = app_contracts'at   第2行

Answer 1

您在“WHERE”之前缺少“FROM”子句。

SELECT app_contracts。*，app_customers.id as customer，app_boards.id as board
FROM app_customers，app_contracts
在哪里app_customers.id = app_contracts.customer_id
AND app_boards.id = app_contracts.board_id
ORDER BY app_contracts.id DESC

Answer 2

你需要在你的WHERE子句

之前选择FROM某事（比如表）

Answer 3

没有FROM子句

Answer 4

这个必须工作：

 SELECT app_contracts.*, app_customers.id as customer, app_boards.id as board
 FROM app_customers, app_contracts, app_boards
 WHERE app_customers.id=app_contracts.customer_id 
 AND app_boards.id=app_contracts.board_id 
 ORDER BY app_contracts.id DESC

Answer 5

您尚未指定从中选择数据的表格。它应该更多的形式：

SELECT app_contracts.*, app_customers.id as customer, app_boards.id as board
FROM app_contracts, app_customers, app_boards
JOIN ...
WHERE app_customers.id=app_contracts.customer_id 
AND app_boards.id=app_contracts.board_id 
ORDER BY app_contracts.id DESC

其中JOIN ...指定三个表应该相关的键。