-- auto-generated definition CREATE TABLE table_a ( PK INT(10) NOT NULL PRIMARY KEY, Value VARCHAR(25) NULL ) COMMENT '表A'; 表B：
-- auto-generated definition CREATE TABLE table_b ( PK INT(10) NOT NULL PRIMARY KEY, Value VARCHAR(50) NULL ) COMMENT '表B'; SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A INNER JOIN table_b B ON A.PK = B.PK;SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A LEFT JOIN table_b B ON A.PK = B.PK;SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A RIGHT JOIN table_b B ON A.PK = B.PK;SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A FULL JOIN table_b B ON A.PK = B.PK;上面代码在mysql执行是报错的，因为mysql不支持全连接，只能用以下代码实现效果，含义是左连接+右连接+去重=全连接：
SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A LEFT JOIN table_b B ON A.PK = B.PK UNION SELECT A.PK AS A_PK,A.Value AS A_Value,B.PK AS B_PK,B.Value AS B_Value FROM table_a A RIGHT JOIN table_b B ON A.PK = B.PK;SELECT A.PK AS A_PK, A.Value AS A_Value, B.Value AS B_Value, B.PK AS B_PK FROM Table_A A LEFT JOIN Table_B B ON A.PK = B.PK WHERE B.PK IS NULLSELECT A.PK AS A_PK, A.Value AS A_Value, B.PK AS B_PK, B.Value AS B_Value FROM Table_A A RIGHT JOIN Table_B B ON A.PK = B.PK WHERE A.PK IS NULLSELECT A.PK AS A_PK, A.Value AS A_Value, B.Value AS B_Value, B.PK AS B_PK FROM Table_A A FULL OUTER JOIN Table_B B ON A.PK = B.PK WHERE A.PK IS NULL OR B.PK IS NULL由于mysql不支持full join，只能通过下面代码模拟实现：
SELECT A.PK AS A_PK, A.Value AS A_Value, B.PK AS B_PK, B.Value AS B_Value FROM table_a A LEFT JOIN table_b B ON A.PK = B.PK WHERE B.PK IS NULL UNION ALL SELECT * FROM table_a A RIGHT JOIN table_b B ON A.PK = B.PK WHERE A.PK IS NULL;版权声明：本文内容由互联网用户自发贡献，该文观点仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请联系我们举报，一经查实，本站将立刻删除。
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