Distinct Students Enrolled

The enrollments table has 90 rows, but many students appear in it several times. Return one row with enrollments (COUNT(*), every row) and students_enrolled (how many different student_id values appear, so a student taking four courses counts once). Three students have no enrollments, so the second number is below 30.

Expected result:

+-------------+-------------------+
| enrollments | students_enrolled |
+-------------+-------------------+
|          90 |                27 |
+-------------+-------------------+
1 row

Hints3 available

Topics:

Aggregates & GROUP BY

Code Editor

Tab to indent (Esc then Tab to move on) · Ctrl+Enter to run · Ctrl+Space to expand shortcuts (sel, ins, desc)

Results

Run your SQL to see every statement's output here, then how it compares with the expected answer.

Not sure what is in a table? SHOW TABLES lists them and DESCRIBE students shows the columns — or open the database browser on the left.