NOT IN vs NOT EXISTS

Question

Which of the queries work better and faster?

NOT EXISTS:

SELECT CustomerID, CustomerName 
FROM Eastend..Customers c
WHERE NOT EXISTS (
    SELECT 1 
    FROM Eastend..[Order Details] od 
    WHERE c.CustomerId = od.CustomerId)

Or NOT IN:

SELECT CustomerID, CustomerName 
FROM Eastend..Customer c
WHERE c.CustomerID NOT IN (
    SELECT CustomerID 
    FROM Eastend..[Order Details])

It says both the queries do the same thing, but which one is recommended more?

Answer 1

In my opinion, the most efficient way to do this would be:

SELECT CustomerID, CustomerName 
    FROM Eastend..Customer c  
          outer join Eastend..[Order Details] od on c.CustomerId = od.CustomerId)
WHERE od.CustomerId is null