Appendix 2. Exercises list page 3

No.	DB	Level	Task	Stage	T&S
51	A3	3	Find the names of the ships having the largest amount of guns among all the ships with the same displacement (taking into account Outcomes table).	Learn	+
53	A3	1	To within two decimal digits, define the average amount of guns for the battleship classes.	Learn	+
54	A3	2	To within two decimal digits, define the average amount of guns for all the battleships (taking into account Outcomes table).	Learn	+
55	A3	1	For each class, define the year in which the first ship of this class was launched. If year of launch of the head ship is unknown, define the minimum launch year for ships of this class. Result set: class, year.	Learn	+
56	A3	3	For each class, define the number of ships of this class that were sunk in battles. Result set: class, number of sunked ships.	Learn	+
57	A3	3	For each class, consisting of at least three ships, define the number of ships (that must be at least 1) of this class sunk in battles. Result set: class, number of sunken ships.	Learn	+
70	A3	3	Point out the battles in which at least three ships from the same country took part.	Learn	+
(-2)	A3	2	For each country, find the year, in which the maximal number of ships had been launched. In the case of more than one year in question, take a minimal year. Result set: country, number of ships, year	Rating	+
19	A3	1	Define the names of all the ships in the database which were definitely launched before 1941.	Rating	+

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SQL Problems and solutions