SQL "*=" operator

Question

Possible Duplicate:
Transact-SQL shorthand join syntax?

I ran across a T-SQL script that does something like this in the where clause:

...
where o.obj_code *= c.prv_code

I can't seem to find any documentation on the *= operator. Can anyone explain its use and maybe point to some documentation on it? Is this specific to T-SQL?

Answer 1

It's an old way to do outer joins. Here's an article that explains in more detail.

Answer 2

It is old non-ANSI outer join syntax. Don't use it. Heres and MSDN reference.

Answer 3

Deprecated Outer Join syntax.
In on the list of Deprecated Engine Features:

Use of *= and =*
Use ANSI join syntax. For more information, see FROM (Transact-SQL).

Answer 4

*= is an old way to do left outer joins that came from Oracle. I found a mention to it in the SQL Server docs once as something they highly recommended not doing.

Here's some info on it from MS:

Transact-SQL Joins

Answer 5

That's the old syntax for a left outer join, and was deprecated from SQL Server 2005 upwards.