Shawn and Sarah SQL queries solution

school_queries.sql

@@ -0,0 +1,95 @@
+select * from classes;
+
+select class_name, credits from classes
+where credits > 3;
+
+select * from classes 
+where credits % 2 = 0;
+
+select * from enrollments 
+join students 
+on enrollments.student_id = students.id 
+where students.first_name = 'Tianna' 
+AND enrollments.grade IS NULL;
+
+select students.first_name, * from enrollments 
+join students 
+on enrollments.student_id = students.id 
+where students.first_name = 'Tianna' 
+AND enrollments.grade IS NULL;
+
+select first_name, class_name from enrollments 
+join students
+on enrollments.student_id = students.id 
+join classes
+on enrollments.class_id = classes.id
+where students.first_name = 'Tianna' 
+AND enrollments.grade IS NULL;
+
+select first_name, last_name from students
+where first_name ilike('%t%') OR
+last_name ilike('%t%') AND
+birthdate < '1986-01-01'::date;
+
+select avg(age(current_date, birthdate)) from students;
+
+select first_name, last_name, line_1, city, state_name, zipcode from addresses
+join students on students.address_id = addresses.id
+where city ilike ('% %');
+
+select avg(credits) from classes;
+
+select first_name, last_name from students
+join enrollments on
+students.id = enrollments.student_id
+where grade like 'A%';
+
+select first_name, sum(credits) from students
+join enrollments
+on students.id = enrollments.student_id
+join classes
+on classes.id = enrollments.class_id
+group by first_name;
+
+select first_name, sum(credits) from students
+join enrollments
+on students.id = enrollments.student_id
+join classes
+on classes.id = enrollments.class_id
+where grade is not null
+group by first_name;
+
+select first_name, class_name from students
+join enrollments
+on students.id = enrollments.student_id
+join classes
+on classes.id = enrollments.class_id
+group by first_name, class_name
+order by 2;
+
+select first_name, last_name, birthdate from students
+where birthdate >= '1982-01-01' AND
+birthdate <= '1985-12-31';
+
+--insert into enrollments (student_id, class_id)
+-- (select student_id from enrollments
+-- join students
+-- on students.id = enrollments.student_id
+-- where last_name = 'Rohan'
+-- limit 1)
+-- (select class_id from classes
+-- join enrollments
+-- on classes.id = enrollments.class_id
+-- where class_name = 'PHYS 218');
+
+-- --INSERT into enrollments (student_id, class_id)
+-- SELECT student_id, class_id
+-- FROM students, enrollments, classes 
+-- WHERE students.last_name = 'Rohan'
+--   AND classes.class_name = 'PHYS 218';
+
+insert into enrollments (student_id, class_id, grade)
+select * from 
+ (select id from students where first_name='Andre' and last_name='Rohan' limit 1) x
+,(select id from classes where class_name='PHYS 218' limit 1) y
+,(select 'A') z;