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  • not in 的优化

    //----------------------  建表1  ----------------------  

    create table TESTTABLE
    (
    id1 VARCHAR2(12),
    name VARCHAR2(32)
    )
    select t.id1,t.name from TESTTABLE t

    insert into TESTTABLE (ID1, NAME)
    values ('1', 'zhangsan');

    insert into TESTTABLE (ID1, NAME)
    values ('2', 'lisi');

     //----------------------  建表2  ----------------------


    create table test_user
    (
    id VARCHAR2(12),
    name VARCHAR2(32),
    age number(2)
    )
    select t.id,t.name,t.age from test_user t


    insert into test_user (ID, NAME,age)
    values ('1', '张三',12);

    insert into test_user (ID, NAME,age)
    values ('2', '李四',12);

    insert into test_user (ID, NAME,age)
    values ('3', '王五',12);

    使用not in的sql:

    select ID,name from test_user where ID not in (select ID1 from TESTTABLE)

    使用exit的sql:

    SELECT T.id,T.name FROM test_user T WHERE NOT EXISTS ( SELECT 'G' FROM TESTTABLE TT WHERE TT.id1 = T.id )

    使用left join的sql:

    select test_user.ID,test_user.name,TESTTABLE.ID1,TESTTABLE.NAME from test_user left join TESTTABLE on test_user.id=TESTTABLE.ID1 where TESTTABLE.name is null

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  • 原文地址:https://www.cnblogs.com/kongxc/p/9310637.html
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