Week2 Sql

week-1/mandatory/2-classes-db/CREATE TABLE mentors (

@@ -0,0 +1,9 @@
+CREATE TABLE mentors (
+  id        SERIAL PRIMARY KEY,
+  name      VARCHAR(30) NOT NULL,
+  email     VARCHAR(120) NOT NULL,
+  address   VARCHAR(120),
+  city      VARCHAR(30),
+  postcode  VARCHAR(12),
+  country   VARCHAR(20)
+);

week-1/mandatory/2-classes-db/task.md

@@ -17,21 +17,95 @@ When you have finished all of the questions - open a pull request with your answ
 
 1. Create a new database called `cyf_classes` (hint: use `createdb` in the terminal)
 2. Create a new table `mentors`, for each mentor we want to save their name, how many years they lived in Glasgow, their address and their favourite programming language.
+
+   CREATE TABLE mentors (
+  id        SERIAL PRIMARY KEY,
+  name      VARCHAR(30) NOT NULL,
+  yearsinglasgow  INT NOT NULL,
+  address   VARCHAR(120) NOT NULL,
+  favlang     VARCHAR(40)
+
+);
 3. Insert 5 mentors in the `mentors` table (you can make up the data, it doesn't need to be accurate ;-)).
+   INSERT INTO MENTORS(name, yearsinglasgow, address, favlang) VALUES('Ebenezer Joshua', 5, '1 Georgia Street,Glasgow', 'AF44TO');
+   INSERT INTO MENTORS(name, yearsinglasgow, address, favlang) VALUES('Donald Tramp',25, '2 Georgia Nose,Glasgow', 'AE58TO');
+   INSERT INTO MENTORS(name, yearsinglasgow, address, favlang) VALUES('Mayor Daniels', 19, '381 Alphonso Road,Glasgow', 'AF88TO');
+   INSERT INTO MENTORS(name, yearsinglasgow, address, favlang) VALUES('John Rawlings', 47, '90 Konado Street,Glasgow', 'TY74TO');
+   INSERT INTO MENTORS(name, yearsinglasgow, address, favlang) VALUES('Freddie Bo', 20, '303 Poke Your Nose,Glasgow', 'ZP99LO');
 4. Create a new table `students`, for each student we want to save their name, address and if they have graduated from Code Your Future.
+
+   CREATE TABLE students (
+  id         SERIAL PRIMARY KEY,
+  address    VARCHAR(120) NOT NULL,
+  cyfgraduate BOOLEAN NOT NULL
+);
 5. Insert 10 students in the `students` table.
+   INSERT INTO STUDENTS(name, address, cyfgraduate) VALUES('John Smith', '123 CHurch Street,Glasgow', TRUE);
+   INSERT INTO STUDENTS(name, address, cyfgraduate) VALUES('Joe Diggie', '45 St Johns Street,Glasgow', FALSE);
+     INSERT INTO STUDENTS(name, address, cyfgraduate) VALUES('Osagie Jonas', '563 Joker Street,Glasgow', TRUE);
+      INSERT INTO STUDENTS(name, address, cyfgraduate) VALUES('Joyce Offei', '123 Nosey Jobs,Glasgow', TRUE);
+       INSERT INTO STUDENTS(name, address, cyfgraduate) VALUES('John Jovi', '78 Obstruction Street,Glasgow', TRUE);
 6. Verify that the data you created for mentors and students are correctly stored in their respective tables (hint: use a `select` SQL statement).
 7. Create a new `classes` table to record the following information:
 
    - A class has a leading mentor
    - A class has a topic (such as Javascript, NodeJS)
    - A class is taught at a specific date and at a specific location
 
+ CREATE TABLE classes (
+  id         SERIAL PRIMARY KEY,
+  student_id  INT references students(id),
+  mentor_id  INT references mentors(id),
+  topic  VARCHAR(120) NOT NULL,
+ location    VARCHAR(120) NOT NULL,
+ datetaught   DATE NOT NULL
+);
+
 8. Insert a few classes in the `classes` table
-9. We now want to store who among the students attends a specific class. How would you store that? Come up with a solution and insert some data if you model this as a new table.
+9.  We now want to store who among the students attends a specific class. How would you store that? Come up with a solution and insert some data if you model this as a new table.
+
+insert into classes(student_id, mentor_id, topic, location, datetaught) values (4, 2, 'Javascript','Glasgow','20-04-20' );
 10. Answer the following questions using a `select` SQL statement:
     - Retrieve all the mentors who lived more than 5 years in Glasgow
+   Ans :
+   select * from mentors where yearsinglasgow > 5;
+ id |     name      | yearsinglasgow |          address           | favlang
+----+---------------+----------------+----------------------------+---------
+  2 | Donald Tramp  |             25 | 2 Georgia Nose,Glasgow     | CSS
+  3 | Mayor Daniels |             19 | 381 Alphonso Road,Glasgow  | React
+  4 | John Rawlings |             47 | 90 Konado Street,Glasgow   | HTML
+  5 | Freddie Bo    |             20 | 303 Poke Your Nose,Glasgow | SQL
+(4 rows)
+
     - Retrieve all the mentors whose favourite language is Javascript
+   select * from mentors where favlang = 'Javascript';
+cyf_classes=# select * from mentors where favlang = 'Javascript';
+ id |      name       | yearsinglasgow |         address          |  favlang
+----+-----------------+----------------+--------------------------+------------
+  1 | Ebenezer Joshua |              5 | 1 Georgia Street,Glasgow | Javascript
+(1 row)
     - Retrieve all the students who are CYF graduates
+Ans -  select * from students where cyfgraduate = true;
+      id |            address            | cyfgraduate |     name
+----+-------------------------------+-------------+--------------
+  1 | 123 CHurch Street,Glasgow     | t           | John Smith
+  3 | 563 Joker Street,Glasgow      | t           | Osagie Jonas
+  4 | 123 Nosey Jobs,Glasgow        | t           | Joyce Offei
+  5 | 78 Obstruction Street,Glasgow | t           | John Jovi
+(4 rows)
     - Retrieve all the classes taught before June this year
+Ans - select * from classes where datetaught < '2020-05-31';
+ id | student_id | mentor_id | topic | location | datetaught
+----+------------+-----------+-------+----------+------------
+  2 |          2 |         3 | HTML  | Glasgow  | 2015-09-20
+  3 |          2 |         1 | CSS   | Glasgow  | 2008-11-20
+  4 |          1 |         3 | React | London   | 2017-12-20
+(3 rows)
+
     - Retrieve all the students (retrieving student ids only is fine) who attended the Javascript class (or any other class that you have in the `classes` table).
+Ans : select student_id from classes where topic='Javascript';
+ student_id
+------------
+          1
+          4
+(2 rows)