SQL Multiple Joins多个地方

Question

我有三个表是问题。类别，词汇& tex。我试图弄清楚如何在查询中有多个连接，我认为只要您正确引用它们，就可以添加尽可能多的连接。

所以，完美的自己有以下两项工作：

1.

SELECT 
categories.ID AS ID, 
categories.ParentID AS ID, 
vocabulary.value AS Name 
FROM categories 
INNER JOIN vocabulary 
ON categories.sid=vocabulary.sid 
WHERE vocabulary.langid=1 

2.

SELECT 
categories.ID AS ID, 
categories.ParentID AS ID, 
tex.value AS Description 
FROM categories 
INNER JOIN tex 
ON categories.tid=tex.tid 
WHERE tex.langid=1 

但是，如果我尝试如下把它们结合在一起，它不行。

categories.ID AS ID, 
categories.ParentID AS ID, 
vocabulary.value AS Name 
tex.value AS Description 
FROM categories 
INNER JOIN tex 
ON categories.tid=tex.tid 
WHERE tex.langid=1 

INNER JOIN vocabulary 
ON categories.sid=vocabulary.sid 
WHERE vocabulary.langid=1 

任何想法？

在此先感谢 约翰

Answer 1

在MySQL，当你有相同名称的列，其中一人才会显示。您需要通过提供ALIAS来唯一标识它们。而且，您可以将条件放在ON子句或WHERE子句中，由于它使用INNER JOIN可能会产生相同的结果。

SELECT categories.ID AS CategoryID, 
     categories.ParentID AS CategoryParentID, 
     vocabulary.value AS Name 
     tex.value AS Description 
FROM categories 
     INNER JOIN tex 
      ON categories.tid = tex.tid 
     INNER JOIN vocabulary 
      ON categories.sid = vocabulary.sid 
WHERE vocabulary.langid = 1 AND 
     tex.langid = 1