Enrollments per month
Medium · School database · Date functions, GROUP BY
Count the enrollments made in each month, using enrolled_on. The enrollments cover more than one year.
Return the month as text in YYYY-MM form (for example 2025-04) and the number of enrollments, in that order, sorted by month, earliest first.
Expected result
| month | enrollments |
|---|---|
| 2025-04 | 18 |
| 2025-05 | 7 |
| 2025-06 | 7 |
| 2025-07 | 3 |
| 2026-01 | 2 |
| 2026-04 | 3 |
The school tables
courses: 10 rows, first 5 shown
| id | name | teacher_id | credits |
|---|---|---|---|
| 1 | Physics | 1 | 4 |
| 2 | Chemistry | 2 | 4 |
| 3 | Mathematics | 3 | 5 |
| 4 | English | 4 | 3 |
| 5 | Biology | 5 | 4 |
enrollments: 40 rows, first 5 shown
| id | student_id | course_id | marks | enrolled_on |
|---|---|---|---|---|
| 1 | 1 | 1 | 88 | 2025-04-07 |
| 2 | 1 | 3 | 88 | 2025-04-07 |
| 3 | 2 | 2 | 91 | 2025-04-08 |
| 4 | 2 | 4 | 86 | 2025-04-08 |
| 5 | 3 | 1 | 72 | 2025-04-09 |
students: 24 rows, first 5 shown
| id | name | gender | class | section | city | dob | |
|---|---|---|---|---|---|---|---|
| 1 | Aarav Sharma | M | 12 | A | Delhi | 2008-05-14 | aarav.sharma@example.com |
| 2 | Priya Nair | F | 12 | A | Kochi | 2008-09-02 | priya.nair@example.com |
| 3 | Rohan Gupta | M | 12 | B | Delhi | 2008-01-23 | NULL |
| 4 | Ananya Iyer | F | 12 | B | Chennai | 2008-11-30 | ananya.iyer@example.com |
| 5 | Kabir Singh | M | 12 | C | Chandigarh | 2007-12-19 | kabir.singh@example.com |
teachers: 8 rows, first 5 shown
| id | name | subject | city | joined_on |
|---|---|---|---|---|
| 1 | Sunita Mehra | Physics | Delhi | 2012-06-01 |
| 2 | Rajesh Kumar | Chemistry | Delhi | 2015-07-15 |
| 3 | Lakshmi Krishnan | Mathematics | Chennai | 2010-04-01 |
| 4 | David Thomas | English | Kochi | 2018-06-20 |
| 5 | Farah Qureshi | Biology | Mumbai | 2016-08-01 |
-- Write your SQL here