Database 减号运算符和不存在运算符在oracle中是否会产生相同的结果

有谁能帮助确认oracle中的减号运算符和not exists是否返回相同的结果集

问候,，

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Mayuran

这里有证据证明减号和不存在查询不会返回相同的结果：

减号查询

with t1 as (select 1 id, 'a' val from dual union all
            select 1 id, 'a' val from dual union all
            select 2 id, 'b' val from dual),
     t2 as (select 2 id, 'b' val from dual union all
            select 3 id, 'c' val from dual)
select id, val
from   t1
minus
select id, val
from   t2;

with t1 as (select 1 id, 'a' val from dual union all
            select 1 id, 'a' val from dual union all
            select 2 id, 'b' val from dual),
     t2 as (select 2 id, 'b' val from dual union all
            select 3 id, 'c' val from dual)
select id, val
from   t1
where  not exists (select null
                   from   t2
                   where  t1.id = t2.id
                   and    t1.val = t2.val);

负结果

        ID VAL
---------- ---
         1 a  

        ID VAL
---------- ---
         1 a  
         1 a  

不存在查询

with t1 as (select 1 id, 'a' val from dual union all
            select 1 id, 'a' val from dual union all
            select 2 id, 'b' val from dual),
     t2 as (select 2 id, 'b' val from dual union all
            select 3 id, 'c' val from dual)
select id, val
from   t1
minus
select id, val
from   t2;

with t1 as (select 1 id, 'a' val from dual union all
            select 1 id, 'a' val from dual union all
            select 2 id, 'b' val from dual),
     t2 as (select 2 id, 'b' val from dual union all
            select 3 id, 'c' val from dual)
select id, val
from   t1
where  not exists (select null
                   from   t2
                   where  t1.id = t2.id
                   and    t1.val = t2.val);

不存在结果

        ID VAL
---------- ---
         1 a  

        ID VAL
---------- ---
         1 a  
         1 a  

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谢谢你的回答