SQL - Append Identity Column in Existing Temp table

Question

I want to update my temp table records. But my existing Temp table does not have any unique column. So I need to append Identity column and update all the records based on that Identity column.

For example, If my temp table has 1000 records without any unique column values. I need to number all these 1000 records and update values.

while(@count < identity_value)
begin
update #temp
Name = 'Gold'
where identity = @count
@count = @count+1
End

I can Alter table option but in my case records are already inserted into my temp table. So I need to loop thorugh it by adding Identity column.

Answer 1

There is no need to do an UPDATE . The identity column is going to be populated when it is created. All you need is:

ALTER TABLE #temp
ADD Id INT Identity(1, 1)
GO

Id field will be populated and it will hold values 1, 2, ..., 1000 .

Answer 2

You don't need loops. See this simplified example:

CREATE TABLE #temp
(
    Name varchar(10)
)
INSERT #temp VALUES ('A'),('B')

--Add identity column
ALTER TABLE #temp ADD ID int IDENTITY