Question

I am using SQL Server 2012 and am creating a table in the following way:

SELECT x, y
INTO CampRegistration
FROM tableA

UNION

SELECT x, y
FROM tableB

x and y are not primary keys. I wish for the CampRegistration table to have an additional column that is an integral surrogate primary key ie. something like an IDENTITY.

How can I do this, either by modifying the SELECT INTO or adding and populating the column afterwards?

Answer 1

The other answers add the row number but don’t make it a key and also don’t help when you want to add a new registration. Here is how, after you’ve run your SELECT INTO, you can add an IDENTITY column and make it the key:

ALTER TABLE dbo.CampRegistration
  ADD RegistrationID INT IDENTITY(1,1);

ALTER TABLE dbo.CampRegistration 
  ADD CONSTRAINT PK_CampRegistration
  PRIMARY KEY (RegistrationID);