Both queries will give different results.
A SQL Query to display all the customers, who are either belongs to the city New York or not had a grade above 100 i.e. grade is less than or equal to 100.
It will return the following 3 tuples
customer_id cust_name city grade salesman_id
----------- ------------ ---------- ---------- -----------
3002 Nick Rimando New York 100 5001
3007 Brad Davis New York 200 5001
3009 Geoff Camero Berlin 100 5003
Now, coming to your SQL queries, i think first is correct and second is incorrect. Also verified them online.
Second correct query should be :
whereas your second query results in :
which is incorrect!