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

Good Question & Matt's was a good answer. To expand on the syntax a little if the oldtable has an identity a user could run the following:

SELECT col1, col2, IDENTITY( int ) AS idcol
INTO #newtable
FROM oldtable

That would be if the oldtable was scripted something as such:

CREATE TABLE [dbo].[oldtable]
(
    [oldtableID] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
    [col1] [nvarchar](50) NULL,
    [col2] [numeric](18, 0) NULL,
)