使用SQL子查詢的表名

Question

我想從用戶，其表名存儲在用戶的列表，像這樣得到的所有具體比分：

SELECT Score 
from (SELECT tablenameOfUser FROM `Users`) 
WHERE X='something' 
    AND Y='somethingElse' 
ORDER BY Score 

我得到的錯誤：

1248 - Every derived table must have its own alias

Answer 1

錯誤消息說明了這一切。您需要派生表上的別名。

SELECT Score 
from (SELECT tablenameOfUser FROM `Users`) 
WHERE X='something' 
    AND Y='somethingElse' 
ORDER BY Score 

應該是：

SELECT Score 
from (SELECT tablenameOfUser FROM `Users`) yourAlias 
WHERE X='something' 
    AND Y='somethingElse' 
ORDER BY Score 

你的子查詢不僅具有tablenameOfUser列，因此Score，X和Y，將無法使用，你的查詢仍然會失敗。