MySQL全外连接请帮助

Question

我知道MySQL全外连接是语法错误。 我有一个完整的外连接mysql5想创建一个类似的查询。 我该怎么办？

Answer 1

You can emulate FULL OUTER JOIN using UNION (from MySQL 4.0.0 on): 

with two tables t1, t2: 

SELECT * FROM t1 
LEFT JOIN t2 ON t1.id = t2.id 
UNION 
SELECT * FROM t1 
RIGHT JOIN t2 ON t1.id = t2.id 

with three tables t1, t2, t3: 

SELECT * FROM t1 
LEFT JOIN t2 ON t1.id = t2.id 
LEFT JOIN t3 ON t2.id = t3.id 
UNION 
SELECT * FROM t1 
RIGHT JOIN t2 ON t1.id = t2.id 
LEFT JOIN t3 ON t2.id = t3.id 
UNION 
SELECT * FROM t1 
RIGHT JOIN t2 ON t1.id = t2.id 
RIGHT JOIN t3 ON t2.id = t3.id