TASK DEFINITION: In this task you are expected to write an SQL query that will return the data asked for in the question. An SQL query works by selecting data from a table where certain conditions apply. A table contains columns where every row in that table must have a value for each column. Every table has a primary key that uniquely identifies each row, usually an id. To choose which columns are returned you specify that after the "SELECT" statement. Next, you use a "FROM" statement to specify what tables you want to select the data from. When you specify a table you can rename it with the "AS" statement. You can reference that table by whatever name follows the "AS" statement. If you want to select data from multiple tables you need to use the "JOIN" statement. This will join the tables together by pairing a row in one table with every row in the other table (Cartesian Product). To limit the number of rows returned you should use the "ON" statement. This will only return rows where the condition specified after the statement is true, this is usually an equals operator with primary keys. You can also use the "WHERE" statement to specify that only rows with column values statisfying a certain condition, should be returned. The "GROUP BY" statement will group rows together that have equal column values for whatever columns follows the statement. The "HAVING" statement will return groups that statisfy whatever condition follows the statement. Any column(s) being returned from grouped rows must either be an aggregate function, (AVG, MAX, COUNT, SUM, ...) of a column, or the column(s) that the data was grouped by. To sort the returned data you can use the "ORDER BY" command which will order the data by whatever aggregate function or column follows the statement. The "DESC" statement will sort in descending order and the "ASC" statement will sort in ascending order. Finally, you can use the "LIMIT" statement to return a certain number of rows. When "*" is used in an SQL statement every column is returned. For example, SELECT * FROM table WHERE attribute = 1, will select every column from rows with the attribute column equal to 1.
PROBLEM: What are the titles of all movies that have not been rated?

SOLUTION: SELECT title FROM Movie WHERE mID NOT IN (SELECT mID FROM Rating)

PROBLEM: What are the first and last names of all drivers who participated in the Australian Grand Prix but not the Chinese Grand Prix?

SOLUTION: SELECT T3.forename ,  T3.surname FROM races AS T1 JOIN results AS T2 ON T1.raceid = T2.raceid JOIN drivers AS T3 ON T2.driverid = T3.driverid WHERE T1.name = "Australian Grand Prix" EXCEPT SELECT T3.forename ,  T3.surname FROM races AS T1 JOIN results AS T2 ON T1.raceid = T2.raceid JOIN drivers AS T3 ON T2.driverid = T3.driverid WHERE T1.name = "Chinese Grand Prix"

PROBLEM: What are the titles of films that are either longer than 100 minutes or rated PG other than those that cost more than 200 to replace?

SOLUTION:
SELECT title FROM film WHERE LENGTH  >  100 OR rating  =  'PG' EXCEPT SELECT title FROM film WHERE replacement_cost  >  200

