Database: boat_1
Question: Find the id of Sailors (sid) that reserved red and blue boat.
SQL:
SELECT DISTINCT T2.sid FROM Boats AS T1 JOIN Reserves AS T2 ON  T1.bid  =  T2.bid WHERE T1.color  =  'red' INTERSECT SELECT DISTINCT T2.sid FROM Boats AS T1 JOIN Reserves AS T2 ON  T1.bid  =  T2.bid WHERE T1.color  =  "blue"