Combine Multiple Query Results with UNION ALL

SELECT customer_id, first_name, last_name, 'Active' AS status
FROM customers
WHERE is_active = TRUE

UNION ALL

SELECT customer_id, first_name, last_name, 'Inactive' AS status
FROM customers
WHERE is_active = FALSE;

How it works: The `UNION ALL` operator combines the result sets of two or more `SELECT` statements into a single result set. Unlike `UNION` (which removes duplicate rows), `UNION ALL` includes all rows from all queries, making it efficient when you don't need distinct results. This is useful for consolidating data from different but structurally similar queries.