Please describe what each code is doing below:

1. a) Select department_id, job_id, SUM(salary)

From employees

Where department_id < 50

Group by department_id, job_id

b) Select department_id, job_id, SUM(salary)

From employees

Where department_id < 50

Group by rollup (department_id, job_id)

c) Select department_id, job_id, SUM(salary)

From employees

Where department_id < 50

Group by CUBE (department_id, job_id)

d) Select department_id, job_id, SUM(salary)

From employees

Where department_id < 50

Group by Grouping Sets

((job_id, manager_id),(department_id, job_id),(department_id, manager_id))

e) Select last_name,job_id,department_id

From employees

Order by job_id;

f) Select department_id,department_name

From departments

Where department_name = 'Marketing'

g) Select title,year

From d_cds

Where year IN (2000,2007,2010);

Select year

From d_cds

Where cd_number < 93;

h) Select year

From d_cds

Where producer = 'The Music Man';

i) Select title,producer, year

From d_cds

Where year < 2001;