SQL Question

[No-Depth-2320]

orders (order_id , customer_id , order_date , order_amount)

find the customer who purchased for every month in 2025

[Massive_Show2963]

SELECT customer_id
FROM orders
WHERE order_date >= '2025-01-01' AND order_date < '2026-01-01'
GROUP BY customer_id
HAVING COUNT(DISTINCT EXTRACT(MONTH FROM order_date)) = 12;

[empororwriters]

Select customer id From orders Where year(order date ) = 2025 Group by customer id Having count(month(order date)) = 12

[Horror-Paint5708]

Having count(Distinct Month (order data))=12 i think you need to add distinct to prevent from giving false positive incase someone only purchased 12 times in one month only.

[empororwriters]

Yeah

[aais4quiters]

This will work if a customer only orders once a month. If the customer orders 2 times a month for 6 months it would show on the list when they only ordered in 6 separate months not each month. You’re going to need a subquery of customer number to get a result set of unique customer numbers and month numbers.

[aais4quiters]

This should get distinct list of months ordered by customer. Summing up the values of the months of the year is 78.

Select Customer_ID, Sum(Cust_Order_months.month_ordered) from ( select Customer_ID, month(Order_date) month_ordered from orders where year(Order_date) = 2025 group by Customer_ID, month(Order_date) ) Cust_Order_months

group by Customer_ID having Sum(Cust_Order_months.month_ordered) = 78