Question

What is the fastest way to loop thru a Query in T-SQL .
1) Cursors or
2) Temp tables with Key added or
any thing else.

Answer 1

I don’t think you need a cursor for that (your comment about concat) if I understand what you’re going for.
Here’s one of mine that grabs all the phone numbers for a contact and plops them in a field and returns it.

DECLARE @numbers VARCHAR(255)

SELECT @numbers = COALESCE(@numbers + ' | ','') + PHONE_NUMB FROM my_table (NOLOCK)
WHERE CONTACT_ID=@contact_id   RETURN @numbers