In SQL

users(email, name, pwd, city, gender) products(pid, descr) sales(sid, lister, pid, edate, descr, cond, rprice) bids(bid, bidder, sid, bdate, amount) items(sid, no, pid, descr) reviews(reviewer, reviewee, rating, rtext, rdate) previews(rid, pid, reviewer, rating, rtext, rdate) 7. For each user who has had some bids, list the user email, the total number of distinct sales the user has had bids on, the number of winning bids, and the total dollar amount of the wining bids. The user has a winning bid if the sale is over (i.e., the end date is in the past), the user has the highest bid and the bid amount is not less than the reserved price. The result should include users who have no winning bids. Hint: subqueries can be used in the from clause