Exercise: Pivoting and Unpivoting Data
Last Updated: May 12, 2026
1 min read
For this exercise, we will work with below data:
SQL
Exercise 1
Easy
Write a query using conditional aggregation that pivots payments into one row per user with columns completed, refunded, and failed showing the count of payments in each status.
SQL
Expected Query
Expected Output
Exercise 2
Hard
Using CROSS JOIN LATERAL with VALUES, write a query that unpivots the payments table to produce one row per (payment_id, metric, value) triple, where metric is either 'amount' or 'refund_amount'. Filter to payments made by user 3.
SQL