diff --git a/answers/exercise1.sql b/answers/exercise1.sql index e69de29..8cd9335 100644 --- a/answers/exercise1.sql +++ b/answers/exercise1.sql @@ -0,0 +1,3 @@ +SELECT * FROM Enrolments +LEFT JOIN Students +ON Students.StudentID = Enrolments.StudentID; diff --git a/answers/exercise2.sql b/answers/exercise2.sql index e69de29..0196411 100644 --- a/answers/exercise2.sql +++ b/answers/exercise2.sql @@ -0,0 +1,4 @@ +SELECT * FROM Enrolments +INNER JOIN Students +ON Enrolments.StudentID = Students.StudentID; + diff --git a/answers/exercise3.sql b/answers/exercise3.sql index e69de29..46a95ed 100644 --- a/answers/exercise3.sql +++ b/answers/exercise3.sql @@ -0,0 +1,3 @@ +SELECT * FROM Enrolments +RIGHT JOIN Students +ON Enrolments.StudentID = Students.StudentID; diff --git a/answers/exercise4.sql b/answers/exercise4.sql index e69de29..45b3335 100644 --- a/answers/exercise4.sql +++ b/answers/exercise4.sql @@ -0,0 +1,3 @@ +SELECT Country, COUNT(*) +FROM Students +GROUP BY Country; diff --git a/answers/exercise5.sql b/answers/exercise5.sql index e69de29..fccc1a8 100644 --- a/answers/exercise5.sql +++ b/answers/exercise5.sql @@ -0,0 +1,4 @@ +SELECT Country, COUNT(*) +FROM Students +GROUP Country + ORDER BY COUNT(*) DESC; diff --git a/answers/exercise6.sql b/answers/exercise6.sql index e69de29..2bd4c55 100644 --- a/answers/exercise6.sql +++ b/answers/exercise6.sql @@ -0,0 +1,5 @@ +SELECT Country, COUNT(*) +FROM Students +GROUP BY Country +HAVING COUNT(*) > 10 +ORDER BY COUNT(*) DESC;