Best way to get identity of inserted row?

Question

What is the best way to get IDENTITY of inserted row?

I know about @@IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY

Answer 1

@@IDENTITY is the last identity inserted using the current SQL Connection. This is a good value to return from an insert stored procedure, where you just need the identity inserted for your new record, and don't care if more rows were added afterward.

SCOPE_IDENTITY is the last identity inserted using the current SQL Connection, and in the current scope -- that is, if there was a second IDENTITY inserted based on a trigger after your insert, it would not be reflected in SCOPE_IDENTITY, only the insert you performed. Frankly, I have never had a reason to use this.

IDENT_CURRENT(tablename) is the last identity inserted regardless of connection or scope. You could use this if you want to get the current IDENTITY value for a table that you have not inserted a record into.

Answer 2

The best (read: safest) way to get the identity of a newly-inserted row is by using the output clause:

create table TableWithIdentity
           ( IdentityColumnName int identity(1, 1) not null primary key,
             ... )

-- type of this table's column must match the type of the
-- identity column of the table you'll be inserting into
declare @IdentityOutput table ( ID int )

insert TableWithIdentity
     ( ... )
output inserted.IdentityColumnName into @IdentityOutput
values
     ( ... )

select @IdentityValue = (select ID from @IdentityOutput)