Transact-SQL速记联接语法? [英] Transact-SQL shorthand join syntax?

问题描述

在处理遗留代码时，我注意到几次，您可以使用

I have noticed a few times when working on legacy code, that you can do left and right outer joins in sql by using the

=*

是正确的外部联接"的简写，并且

as kind of shorthand for "right outer join" and

*=

在以下语句中是左外部连接"的简写形式:

as kind of shorthand for "left outer join" in statements like this:

select table1.firstname, table2.lastname
from table1, table2
where table1.id *= table2.id

我猜想还有其他两个类似的运算符用于不同类型的联接，但是我找不到关于它的任何好的完整文档.那么您知道与文档的任何良好链接吗?

I would guess that there are other operators like these two for the different kinds of joins, but i have not been able to find any good complete documentation about it. So do you know any good links to documentation?

我个人认为，与使用拼写语法相比，使用这些运算符看到的SQL语句更难弄清楚，因此使用速记版本是否有任何好处?

I personaly think that the SQL statements i have seen using these operators are more difficult to figure out than when using the spelled out syntax, so is there any benefits using the shorthand version?

推荐答案

= *和* =在当前的SQL标准中不存在问题，我相信这些运算符将很快被弃用，您应该始终使用标准联接语法.您提到的其他运算符令人困惑，需要删除，当我在数据库对象中看到这些运算符时，我会感到畏缩.

The =* and *= are not complaint with current SQL standards, I believe these operators will be deprecated soon you should always use the standard join syntax. The other operators that you mention are confusing and need to go away, I cringe when I see these in database objects.

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