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  • oracle sql 内连接 左外连接 右外连接 全外连接

    1.创建测试表并准备测试数据
    sec@ora10g> create table a (a number(1),b number(1),c number(1));
    sec@ora10g> create table b (a number(1),d number(1),e number(1));
    sec@ora10g> insert into a values(1,1,1);
    sec@ora10g> insert into a values(2,2,2);
    sec@ora10g> insert into a values(3,3,3);
    sec@ora10g> insert into b values(1,4,4);
    sec@ora10g> insert into b values(2,5,5);
    sec@ora10g> insert into b values(4,6,6);
    sec@ora10g> commit;

    sec@ora10g> select * from a;
           
    A          B          C
    ---------- ---------- ----------
            
    1          1          1
            
    2          2          2
            
    3          3          3


    sec@ora10g> select * from b;

            
    A          D          E
    ---------- ---------- ----------
            
    1          4          4
            
    2          5          5
            
    4          6          6

    2. 内连接
    sec@ora10g> select * from a, b where a.a=b.a;
    另外一种写法如下
    sec@ora10g> select * from  a inner join b on a.a=b.a;

            
    A        B          C          A          D          E

    -------- ---------- ---------- ---------- ---------- ----------
            
    1        1          1          1          4          4
            
    2        2          2          2          5          5

    3.左外连接
    sec@ora10g> select * from  a,b where a.a=b.a(+);
    另外一种写法如下
    sec@ora10g> select *  from  a  left outer join b on a.a=b.a;

            
    A          B          C          A          D          E
    ---------- ---------- ---------- ---------- ---------- ----------
            
    1          1          1          1          4          4
            
    2          2          2          2          5          5
            
    3          3          3

    4.右外连接
    sec@ora10g> select * from  a,b where a.a(+)=b.a;
    另外一种写法如下
    sec@ora10g> select * from  a  right outer join b on a.a=b.a;

            
    A          B          C          A          D          E
    ---------- ---------- ---------- ---------- ---------- ----------
            
    1          1          1          1          4          4
            
    2          2          2          2          5          5
                                             
                        4          6          6
    5.全外连接
    sec@ora10g> select * from  a full outer join b on a.a=b.a;

            
    A          B          C          A          D          E
    ---------- ---------- ---------- ---------- ---------- ----------
            
    1          1          1          1          4          4
            
    2          2          2          2          5          5
            
    3          3          3
                                             
                        4          6          6

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  • 原文地址:https://www.cnblogs.com/pumushan/p/4661844.html
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