Interview Guides
You are given two PostgreSQL tables that represent the same trade cashflows from different internal sources: one from an execution feed and one from a clearing feed used in a SIG-style reconciliation workflow. Write a query that compares the tables at the trade_date + account_id + symbol level and returns only mismatches.
Your result should show the grouped keys, the total quantity and total notional from each source, and a mismatch status that distinguishes rows missing on one side from rows where both sides exist but the aggregated values differ. Treat NULL quantities or notionals as 0 during aggregation.
