【MySQL】记录7种SQL join语句

1、内连接

SELECT <select...list> 
FROM TableA A 
INNER JOIN TableB B 
ON A.Key=B.Key; 

2、左外连接（包括公共部分）

SELECT <select...list>
FROM　TableA A 
LEFT JOIN TableB B 
ON A.Key=B.Key;

3、右外连接（包括公共部分）

SELECT <select...list>
FROM TableA A 
RIGHT JOIN TableB B 
ON A.Key=B.Key;

4、左外连接（不包括公共部分）

SELECT <select...list>
FROM TableA A 
LEFT JOIN TableB B 
ON A.Key=B.Key 
WHERE B.Key IS NULL;

5、右外连接（不包括公共部分）

SELECT <select...list>
FROM TableA A RIGHT JOIN TableB B 
ON A.Key=B.Key 
WHERE A.Key IS NULL;

6、全外连接

MySQL版本（不支持FULL OUTER JOIN）

SELECT <select...list>
FROM　TableA A 
LEFT JOIN TableB B 
ON A.Key=B.Key;
UNION
SELECT <select...list>
FROM TableA A 
RIGHT JOIN TableB B 
ON A.Key=B.Key;

orcale可以简化：

SELECT <select...list>
FROM TableA A 
FULL OUTER JOIN TableB B
ON A.Key=B.Key

7、交叉外连接

MySQL：

SELECT <select...list>
FROM TableA A 
LEFT JOIN TableB B 
ON A.Key=B.Key 
WHERE B.Key IS NULL;
UNION
SELECT <select...list>
FROM TableA A 
RIGHT JOIN TableB B 
ON A.Key=B.Key 
WHERE A.Key IS NULL;

orcale：

SELECT <select...list>
FROM TableA A 
FULL OUTER JOIN TableB B
ON A.Key=B.Key
WHERE A.Key IS NULL OR B.Key IS NULL;