Question 22
Table: payment
Movie rental payment transactions table
col_name | col_type --------------+-------------------------- payment_id | integer customer_id | smallint staff_id | smallint rental_id | integer amount | numeric payment_ts | timestamp with time zone
Sample results
avg -------------------- 1.234567
Solution
postgres
SELECT AVG(amount)
FROM payment
WHERE DATE(payment_ts) >= '2020-05-01'
AND DATE(payment_ts) <= '2020-05-31';Explanation
This query calculates the average payment amount for the month of May 2020. It selects the "amount" column from the "payment" table and filters the results to only include payments made between May 1st and May 31st of 2020. The "AVG" function then calculates the average of all the payment amounts within that time period.
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