Why are these two queries different? <p>Display the details of the employees who have subscribed for Football and Chess but not for Tennis.</p> <pre><code>SELECT * FROM employee WHERE empid IN (SELECT empid FROM subscription WHERE facid IN (SELECT facid FROM facility WHERE facility = 'Chess' OR facility = 'Football')) AND empid NOT IN (SELECT empid FROM subscription WHERE facid = (SELECT facid FROM facility WHERE facility = 'Tennis')); SELECT DISTINCT empid FROM subscription WHERE facid IN (SELECT facid FROM facility WHERE facility = 'Chess' OR facility = 'Football') AND facid != (SELECT facid FROM facility WHERE facility = 'Tennis'); </code></pre> <p>The first one gives correct result.</p>