Question 181Asked in CIL MT Systems, 27 Feb 2020 (8:00 AM)
Consider the following relational schema Sailors(sid, sname, rating, age)
Consider the following relational schema
Sailors(sid, sname, rating, age)
Reserves(sid, bid, day)
Boats(bid, bname, color)
What is the equivalent of following relational algebra query in SQL query
π_sname ((σ_color='red' Boats) ⋈ Reserves ⋈ Sailors)
ASELECT S.sname, S.rating FROM Sailors S, Reserves R WHERE S.sid = R.sid AND R.bid = B.bid AND B.color = 'red'
BSELECT S.sname FROM Sailors S, Reserves R, Boats B WHERE S.sid = R.sid AND R.bid = B.bid AND B.color = 'red'
CSELECT S.sname FROM Sailors S, Reserves R, Boats B WHERE S.sid = R.sid AND B.color = 'red'
DSELECT S.sname FROM Sailors S, Reserves R, Boats B WHERE R.bid = B.bid AND B.color = 'red'
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Correct answer: (B) SELECT S.sname FROM Sailors S, Reserves R, Boats B WHERE S.sid = R.sid AND R.bid = B.bid AND B.color = 'red'