Winter Sign-Ups Week by Week

Use a recursive CTE named weeks to generate every Monday from 2025-12-01 to 2026-01-12 (seven dates one week apart, stepping with date(…, '+7 days')). Then LEFT JOIN enrollments so each week counts the rows whose enrolled_on falls on or after that Monday and before the next one. Return week_start and signups, sorted by week_start; the three holiday weeks in the middle must show 0.

Expected result:

+------------+---------+
| week_start | signups |
+------------+---------+
| 2025-12-01 |      15 |
| 2025-12-08 |      13 |
| 2025-12-15 |       0 |
| 2025-12-22 |       0 |
| 2025-12-29 |       0 |
| 2026-01-05 |       4 |
| 2026-01-12 |       2 |
+------------+---------+
7 rows

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CTEs

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