在MysqL中,全连接(Full Join)是一种用于同时返回两个表中所有匹配和不匹配的记录的连接查询操作。全连接操作可以通过以下几种方式实现:
- 使用FULL JOIN关键字:
SELECT *
FROM table1
FULL JOIN table2 ON table1.column = table2.column;
- 使用UNION操作符组合LEFT JOIN和RIGHT JOIN查询结果:
SELECT *
FROM table1
LEFT JOIN table2 ON table1.column = table2.column
UNION
SELECT *
FROM table1
RIGHT JOIN table2 ON table1.column = table2.column;
- 使用左右外连接组合LEFT JOIN和RIGHT JOIN查询结果:
SELECT *
FROM table1
LEFT JOIN table2 ON table1.column = table2.column
UNION ALL
SELECT *
FROM table1
RIGHT JOIN table2 ON table1.column = table2.column
WHERE table1.column IS NULL;