Suppose we have a relational database with five tables: Table Key attributes S(sid, A) sid T(tid, B) tid U(uid, C) uid R(sid, tid, D) sid, tid…

Suppose we have a relational database with five tables:

Table	Key attributes
S(sid, A)	sid
T(tid, B)	tid
U(uid, C)	uid
R(sid, tid, D)	sid, tid
Q(tid, uid, E)	tid, uid

Here R implements a many-to-many relationship between the entities implemented with tables S and T, and Q implements a many-to-many relationship between the entities implemented with tables T and U.

(A) Write an SQL query that returns all records of the form sid, uid where sid is the key of an S-record and uid is the key of a U-record and these two records are related through the relations R and Q. Use SELECT and not SELECT DISTINCT in your query.

(B) Write an SQL query that returns records of the form A, C where the A-value is from an S-record and the C-value is from a U-record and these two records are related through the relations R and Q. Use SELECT and not SELECT DISTINCT in your query.