The Question
SQL
Identifying Multi-Year Customer Loyalty
Given a table of tax filing records, identify all users who have used the 'TurboTax' product line to file their taxes for at least three consecutive calendar years. Ensure your solution accounts for users who may have multiple filing entries within the same year and returns a unique list of user IDs in ascending order.
PostgreSQL
Window Func
CTE
LAG
EXTRACT
DISTINCT