这个问题在这里已经有了答案:
Oracle "(+)" Operator
(4 个回答)
How to find LEFT OUTER JOIN or RIGHT OUTER JOIN with ORACLE JOIN (+)
(2 个回答)
6年前关闭。
我对 oracle sql 很陌生,刚遇到一个看起来像这样的查询
SELECT some_field
FROM some_table
WHERE some_other_field=some_value(+);
我对代码进行了简化和 annonimized,但我很好奇
(+)
是什么?在末尾。我不记得在 mssql 世界中看到过。
最佳答案
这是 Oracle 旧的外连接语法:
To write a query that performs an outer join of tables A and B and returns all rows from A (a left outer join), use the LEFT [OUTER] JOIN syntax in the FROM clause, or apply the outer join operator (+) to all columns of B in the join condition in the WHERE clause. For all rows in A that have no matching rows in B, Oracle Database returns null for any select list expressions containing columns of B.
http://docs.oracle.com/cd/B19306_01/server.102/b14200/queries006.htm
关于sql - 查询末尾的 (+) 是什么?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30391767/