From 83e0d713787492908249bffeffe6da87732ce59e Mon Sep 17 00:00:00 2001 From: Dee Date: Sat, 31 Jul 2021 18:59:30 -0400 Subject: [PATCH 1/2] join queries --- answers/exercise1.sql | 3 +++ answers/exercise2.sql | 4 ++++ answers/exercise3.sql | 3 +++ 3 files changed, 10 insertions(+) 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; From a151fd53d6159e4eec8f7eca49706bafe0d2e06c Mon Sep 17 00:00:00 2001 From: Dee Date: Sat, 31 Jul 2021 19:52:22 -0400 Subject: [PATCH 2/2] Group practice --- answers/exercise4.sql | 3 +++ answers/exercise5.sql | 4 ++++ answers/exercise6.sql | 5 +++++ 3 files changed, 12 insertions(+) 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;