Fastest way to determine if record exists

Question

As the title suggests... I\'m trying to figure out the fastest way with the least overhead to determine if a record exists in a table or not.

Sample query:

Answer 1

I've used this in the past and it doesn't require a full table scan to see if something exists. It's super fast...

UPDATE TableName SET column=value WHERE column=value
IF @@ROWCOUNT=0
BEGIN
     --Do work
END