How would you write a query to find customers who have orders but no payments using JOINs?

Difficulty: 5/10

LEFT JOIN, anti-join, NULL handling

Finding Customers Who Have Orders but No Payments Using JOINs

To find customers who have placed orders but have not made any payments, you can use a LEFT JOIN between orders and payments and then filter rows where the payment does not exist (IS NULL). The key idea is: JOIN all orders, then keep only those without matching payments.

Using LEFT JOIN + IS NULL

The LEFT JOIN keeps all orders even if a payment doesn't exist. Rows where payment_id is NULL indicate the order has no payment.

Alternative: Using NOT EXISTS (often faster)

Which Method Should You Use?

1
Use LEFT JOIN + IS NULL when you also want to fetch data from the main tables (e.g., order_id).
2

How would you write a query to find customers who have orders but no payments using JOINs?

Difficulty: 5/10

LEFT JOIN, anti-join, NULL handling

Finding Customers Who Have Orders but No Payments Using JOINs

Using LEFT JOIN + IS NULL

The LEFT JOIN keeps all orders even if a payment doesn't exist. Rows where payment_id is NULL indicate the order has no payment.

Alternative: Using NOT EXISTS (often faster)

Which Method Should You Use?

1
Use LEFT JOIN + IS NULL when you also want to fetch data from the main tables (e.g., order_id).
2

How would you write a query to find customers who have orders but no payments using JOINs?

Finding Customers Who Have Orders but No Payments Using JOINs

How would you write a query to find customers who have orders but no payments using JOINs?

Finding Customers Who Have Orders but No Payments Using JOINs

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