Can someone please explain how the answers for the fisrt 3 (and perhaps the last 2..) were derived? I am familiar with relational algebra, but these are a bit tricky

Each row of the following table shows two queries. In the blank third column of the table write "YES" if the two queries are equivalent, and "NO" if they are not equivalent. Two queries are equivalent if they always return exactly the same answer on all databases All queries refer to a schema containing two relations R(A, B) where A is the primary key and B is a candidate key S(A, B) where A is the primary key (and only key) You may assume that the relations do not contain null values, but do not make any other assumptions about the relations Query 1 Equivalent? (YES/NO) NO YES Query 2 RN S SELECT DISTINCT R.A SELECT R.A FROM R, S WHERE R.B#8 . B SELECT R.A, COUNT(SELECT R.A, COUNT*) FROM R WHERE R. A>3 GROUP BY R.A NO FROM R, S WHERE R,B=S . B YES FROM R GROUP BY R.A HAVING R. A>3