TASK DEFINITION: In this task you are expected to provide an SQL statement from an english description of what that SQL statement does. The description may include multiple steps but you should only ouput one SQL statement that accomplishes every step. 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: Step 1: For each row in Campuses table, find corresponding rows in discipline_enrollments table and in faculty table.
Step 2: find faculty's Year of the results of step 1 whose Undergraduate greater than 400.
Step 3: find the discipline_enrollments's Campus of discipline_enrollments table for which Discipline greater than 1956.
Step 4: show the rows that are in both the results of step 2 and the results of step 3

SOLUTION: SELECT T3.Year FROM Campuses AS T1 JOIN discipline_enrollments AS T2 ON T2.Campus = T1.Id JOIN faculty AS T3 ON T1.Id = T3.Campus WHERE T2.Undergraduate > 400 INTERSECT SELECT T2.Campus FROM discipline_enrollments AS T2 WHERE T2.Discipline > 1956

PROBLEM: Step 1: For each row in artist table, find the corresponding rows in song table.
Step 2: find artist's artist_name of the results of step 1 whose rating greater than 7.
Step 3: find the song's artist_name of song table for which song's country equals Bangladesh.
Step 4: show the rows that are in the results of step 2 but not in the results of step 3

SOLUTION: SELECT T1.artist_name FROM artist AS T1 JOIN song AS T2 ON T1.artist_name = T2.artist_name WHERE T2.rating > 7 EXCEPT SELECT T2.artist_name FROM song AS T2 WHERE T2.country = "Bangladesh"

PROBLEM: Step 1: For each row in wine table, find corresponding rows in grapes table and in appellations table.
Step 2: find without repetition County of the results of step 1 whose Color equals Red

SOLUTION:
SELECT DISTINCT T2.County FROM grapes AS T1 JOIN appellations AS T2 JOIN wine AS T3 ON T1.Grape = T3.Grape AND T3.Appelation = T2.Appelation WHERE T1.Color = "Red"