Write SQL for top spender and non-spenders

## SQL Questions Assume the following schema: - `users(user_id, created_at, ...)` - `transactions(txn_id, user_id, amount, txn_ts)` - `amount` is a positive number for a successful purchase. ### Q1: Biggest spender last month Write a SQL query to find the **user(s)** with the **largest total spend in the previous calendar month**. ### Q2: Users who never spent Write a SQL query to find **users who have never made a purchase** (no rows in `transactions`). > If you need additional assumptions (timezone, refunds, ties), state them explicitly.