INSERT INTO a temp table, and have an IDENTITY field created, without first declaring the temp table?

Question

I need to select a bunch of data into a temp table to then do some secondary calculations; To help make it work more efficiently, I would like to have an IDENTITY column on that

Answer 1

You commented: not working if oldtable has an identity column.

I think that's your answer. The #newtable gets an identity column from the oldtable automatically. Run the next statements:

create table oldtable (id int not null identity(1,1), v varchar(10) )

select * into #newtable from oldtable

use tempdb
GO
sp_help #newtable

It shows you that #newtable does have the identity column.

If you don't want the identity column, try this at creation of #newtable:

select id + 1 - 1 as nid, v, IDENTITY( int ) as id into #newtable
     from oldtable