Write a SQL query to compute a running total of daily signups and compare it to the previous day using LAG or LEAD at Deepmind.
Use the non-null signup dates in signup_events. Treat the previous available signup date as the previous day for comparison.
signup_date, daily_signups, running_total, previous_running_total, and running_total_change.running_total_change should be the current running total minus the previous running total, with the first row compared against zero.| Column | Type | Description |
|---|---|---|
| signup_idPK | INT | Unique identifier for the signup event |
| user_id | VARCHAR(30) | Identifier of the user who signed up |
| signup_date | DATE | Date on which the signup occurred |