Identify Missing Data in Customer Orders

Task

A retail company needs to analyze its customer orders to identify any missing order amounts. Write a SQL query to find customers who have at least one order with a NULL amount.

Requirements

Select customer names from the orders table.
Count the number of orders with NULL amounts for each customer.
Only include customers with at least one NULL order amount in the results.

Schema

orders (id, customer_name, amount, order_date)

id	customer_name	amount	order_date
1	Alice	150	2024-01-01
2	Bob	NULL	2024-01-02
3	Charlie	200	2024-01-03
4	Alice	NULL	2024-01-04
5	Diana	300	2024-01-05
6	Bob	100	2024-01-06
7	Charlie	NULL	2024-01-07
8	Diana	250	2024-01-08

Expected Output

customer_name	null_order_count
Alice	1
Bob	1
Charlie	1

Task

A retail company needs to analyze its customer orders to identify any missing order amounts. Write a SQL query to find customers who have at least one order with a NULL amount.

Requirements

Select customer names from the orders table.
Count the number of orders with NULL amounts for each customer.
Only include customers with at least one NULL order amount in the results.

Schema

orders (id, customer_name, amount, order_date)

id	customer_name	amount	order_date
1	Alice	150	2024-01-01
2	Bob	NULL	2024-01-02
3	Charlie	200	2024-01-03
4	Alice	NULL	2024-01-04
5	Diana	300	2024-01-05
6	Bob	100	2024-01-06
7	Charlie	NULL	2024-01-07
8	Diana	250	2024-01-08

Expected Output

customer_name	null_order_count
Alice	1
Bob	1
Charlie	1

Task

A retail company needs to analyze its customer orders to identify any missing order amounts. Write a SQL query to find customers who have at least one order with a NULL amount.

Requirements

Select customer names from the orders table.
Count the number of orders with NULL amounts for each customer.
Only include customers with at least one NULL order amount in the results.

Schema

orders (id, customer_name, amount, order_date)

id	customer_name	amount	order_date
1	Alice	150	2024-01-01
2	Bob	NULL	2024-01-02
3	Charlie	200	2024-01-03
4	Alice	NULL	2024-01-04
5	Diana	300	2024-01-05
6	Bob	100	2024-01-06
7	Charlie	NULL	2024-01-07
8	Diana	250	2024-01-08

Expected Output

customer_name	null_order_count
Alice	1
Bob	1
Charlie	1

Task

A retail company needs to analyze its customer orders to identify any missing order amounts. Write a SQL query to find customers who have at least one order with a NULL amount.

Requirements

Select customer names from the orders table.
Count the number of orders with NULL amounts for each customer.
Only include customers with at least one NULL order amount in the results.

Schema

orders (id, customer_name, amount, order_date)

id	customer_name	amount	order_date
1	Alice	150	2024-01-01
2	Bob	NULL	2024-01-02
3	Charlie	200	2024-01-03
4	Alice	NULL	2024-01-04
5	Diana	300	2024-01-05
6	Bob	100	2024-01-06
7	Charlie	NULL	2024-01-07
8	Diana	250	2024-01-08

Expected Output

customer_name	null_order_count
Alice	1
Bob	1
Charlie	1

Interview Guides

Task

Requirements

Schema

Expected Output

Identify Missing Data in Customer Orders

Task

Requirements

Schema

Expected Output

Practice SQL

Identify Missing Data in Customer Orders

Task

Requirements

Schema

Expected Output

Identify Missing Data in Customer Orders

Task

Requirements

Schema

Expected Output

Practice SQL