Question

Is there any way to store the identity values just prior to an insert and the new identity values just after an insert into a mapping table? The mapping table will be used to update foreign keys in other tables.

Initially I thought this was possible with the OUTPUT INTO clause but only the inserted values are insertable. I’m not sure how to use the OUTPUT clause all by itself to do the job. Maybe some sort of subquery?

Maybe this is all too complicated and there is a way to use SCOPE_IDENTITY and subqueries to do this.

Any help would be much appreciated.

p.s. Yeah, I know I can solve this by ‘reserving’ identities (insert dummy rows and then delete or DBCC CHECKINDENT), save the newly ‘reserved’ identities and the old identities into the mapping table, update the table with the new identities and finally doing an insert with INSERT_IDENTITIES turned on – but that is messy.

This applies to SQLServer 2008R2.

Here is what doesn’t work:

INSERT 
    [SomeTable]
    OUTPUT
           INSERTED.[Id],
           [Id] -- This doesn't work
        INTO
           [#mappingTable]
SELECT
    (SomeColumns)
FROM
    [#someOtherTable];

Answer 1

It can be done with a MERGE statment and an OUTPUT clause. Too bad no one answered with this info, my coworker showed me though.