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  • SQL各种JOIN

    JOIN(= INNER JOIN):返回匹配的结果,没有匹配则没结果;

    LEFT JOIN(= LEFT OUTER JOIN):返回匹配的与左表的所有数据;

    RIGHT JOIN(= RIGHT OUTER JOIN):返回匹配的与右表的所有数据;

    FULL JOIN(= FULL OUTER JOIN):返回两个表的所有数据,匹配的在同一行。

    在oracle中的测试结果:

    AAA表数据  BBB表数据  CCC表数据

    SELECT * FROM AAA A JOIN BBB B ON A.ID = B.ID;

    SELECT * FROM AAA A JOIN CCC B ON A.ID = B.ID;

    SELECT * FROM AAA A LEFT JOIN BBB B ON A.ID = B.ID;

    SELECT * FROM AAA A LEFT JOIN CCC B ON A.ID = B.ID;

    SELECT * FROM AAA A RIGHT JOIN BBB B ON A.ID = B.ID;

    SELECT * FROM AAA A RIGHT JOIN CCC B ON A.ID = B.ID;

    SELECT * FROM AAA A FULL JOIN BBB B ON A.ID = B.ID;

     

    SELECT * FROM AAA A FULL JOIN CCC B ON A.ID = B.ID;

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  • 原文地址:https://www.cnblogs.com/haizine/p/10910734.html
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