在Oracle 10g中使用左联接删除 [英] Delete with Left Join in Oracle 10g

问题描述

我有以下代码可以在MS SQL Server中正常工作:

I have the following code that works fine in MS SQL Server:

delete grp
from grp
left join my_data
on grp.id1 = my_data.id1
and grp.id2 = my_data.id2
and grp.id3 = my_data.id3
and grp.id4 = my_data.id4
where my_data.id1 is NULL

基本上，我想删除在grp中可以找到的所有匹配项，并且没有任何等价物in my_data.可悲的是，它在Oracle 10g中不起作用.我尝试对左联接(+)使用旧语法，但是它也不起作用.像这样:

Basically, I want to delete all occurrence that can be found in grp and don't have any equivalence in my_data. Sadly, it doesn't work in Oracle 10g. I tried using the old syntax for left join (+) but it doesn't work either. Like this:

delete grp
from grp,
my_data
where grp.id1 = my_data.id1 (+)
and grp.id2 = my_data.id2 (+)
and grp.id3 = my_data.id3 (+)
and grp.id4 = my_data.id4 (+)
and my_data.id1 is NULL

如果我没有多个键，但是我看不到如何在数据中使用它，那么IN子句将起作用.那么，还有什么选择呢?

A IN clause would works if I didn't have multiple keys but I don't see how I could use it with my data. So, what is the alternative?

推荐答案

表和数据:

SQL> create table grp (id1 number null, id2 number null, id3 number null, id4 number null);    
Table created.

SQL> create table my_data (id1 number null, id2 number null, id3 number null, id4 number null);

Table created.

SQL> insert into grp values (1, 2, 3, 4);

1 row created.

SQL> insert into grp values (10, 20, 30, 40);

1 row created.

SQL> insert into grp values (1, 2, 30, 40);

1 row created.

SQL> insert into my_data values (1, 2, 3, 4);

1 row created.

SQL> commit;

Commit complete.

使用in. 注意如果子查询中的ID可以为null，请不要使用. null中的Not in从不返回true.

Using in. Note Do not use if the IDs in the subquery can be null. Not in of null never returns true.

SQL> delete grp where (id1, id2, id3, id4) not in (select id1, id2, id3, id4 from my_data);

2 rows deleted.

SQL> select * from grp;

       ID1        ID2        ID3        ID4
---------- ---------- ---------- ----------
         1          2          3          4

使用exists

SQL> rollback;

Rollback complete.

SQL> delete grp where not exists (select * from my_data where grp.id1 = my_data.id1 and grp.id2 = my_data.id2 and grp.id3 = my_data.id3 and grp.id4 = my_data.id4);

2 rows deleted.

SQL> select * from grp;

       ID1        ID2        ID3        ID4
---------- ---------- ---------- ----------
         1          2          3          4

SQL> 

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