These problems are optional, and are made available at the request of some students wha wanted to practice more SQL. I do not plan to post the solutions, or to discuss these problems in class or in the quiz sections. If you need help with any of them, please come to my office hours, or make a separate appointment. Schema: Likes(drinker, beer) Frequents(drinker, bar) Serves(bar, beer) AGGREGATE QUERIES * for each bar, count the number of drinkers that frequent that bar and that like both 'heineken' and 'bud' * for each bar that serve both 'heineken' and 'bud' count the number of drinkers that frequent that bar * for each bar that serve 'heineken' count the number of drinkers that frequent that bar and that like 'bud' EXISTNENTIAL AND UNIVERSAL QUANTIFIER * find all drinkers that frequent some bar that serves some beer that they like * find all drinkers that frequent only bars that serve some beer that they like * find all drinkers that frequent some bar that serves only beer that they like * find all drinkers that frequent some bar that serves some beer that they don't like * find all drinkers that ferquent some bar that serves only beer that they don't like * find all drinkers that frequent only bars that serve some beer that they don't like * find all drinkers that frequent only bars that serve only beer that they don't like