关系数据库内连接、左连接、右连接图示说明

很多次被问起 内连接、左连接 、 右连接相关的问题。每次的回答都不是很明确，前端时间看到一篇文章用绘图的方式给出了明确的回答。原文的链接为http://www.codinghorror.com/blog/archives/000976.html
内连接 Inner join

SELECT * FROM TableA
INNER JOIN TableB
ON TableA.name = TableB.name

全外连接 Full outer join

SELECT * FROM TableA
FULL OUTER JOIN TableB
ON TableA.name = TableB.name

左外连接 Left outer join

SELECT * FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name

 

 

表A中排除了B中的记录

 

SELECT * FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name
WHERE TableB.id IS null

 

 

A表和B表中互不相等

SELECT * FROM TableA
FULL OUTER JOIN TableB
ON TableA.name = TableB.name
WHERE TableA.id IS null
OR TableB.id IS null

相关资料
The dangerous subtleties of LEFT JOIN and COUNT() in SQL