Compute each member’s current notification status

A member's push-notification preference takes one of two values, 'on' or 'off'. The table pref_snapshot stores a single row per member capturing the preference in force when January ended (2020-01-31). The table feb_log records every notification toggle that happened during February 2020, each row carrying the UTC calendar day and the operation that was applied. Write a PostgreSQL query returning the preference each member holds when February ends (2020-02-29). Every member…