SQL Server: Why Scope_Identity() vs @@identity

In SQL Server we have 3 methods to get the auto-generated identity:

1.      IDENT_CURRENT(‘tablename’)

2.      @@IDENTITY

3.      SCOPE_IDENTITY()

 

But the methods above have some difference:

SQL statement	Limit to specified table	Limit to current session	Limit to current scope
IDENT_CURRENT(‘tablename’)	Yes	No	No
@@IDENTITY	No	Yes	No
SCOPE_IDENTITY()	No	Yes	Yes

That’s why we prefer SCOPE_IDENTITY(). 

 

In MSDN there are also some description/discussion on this topic:

• SCOPE_IDENTITY (Transact-SQL)

  http://msdn.microsoft.com/en-us/library/ms190315.aspx

• Scope_Identity vs @@identity

  http://social.msdn.microsoft.com/Forums/en/transactsql/thread/77caea32-a8a6-479e-95d8-ffdf32cecd3d