Calculate Average Order Value

You are tasked with analyzing sales data to understand the average value of customer orders. Calculating the average order value is crucial for businesses to gauge customer spending habits, assess the effectiveness of marketing campaigns, and make informed pricing decisions.

Problem Description

You need to write an SQL query that calculates the average order_value for all orders in a given table. The query should return a single value representing this average.

Key Requirements:

Calculate the arithmetic mean of the order_value column.
The output should be a single numerical value.

Expected Behavior:

The query should process all rows in the orders table and compute the average of the order_value for each row.

Edge Cases:

Empty Table: If the orders table is empty, what should be returned? (Consider that AVG typically returns NULL for empty sets).
NULL order_value: How should NULL values in the order_value column be handled? (Standard SQL AVG ignores NULL values).

Examples

Example 1:

Input: orders table:

order_id	customer_id	order_value
101	1	50.00
102	2	75.50
103	1	25.00

Output:

60.17

Explanation: The sum of order_value is 50.00 + 75.50 + 25.00 = 150.50. There are 3 orders. The average is 150.50 / 3 = 50.1666... which rounds to 50.17 (assuming typical decimal precision).

Example 2:

Input: orders table:

order_id	customer_id	order_value
201	3	100.00
202	4	NULL
203	3	200.00

Output:

150.00

Explanation: The order_value of 202 is NULL and is ignored in the calculation. The sum of order_value is 100.00 + 200.00 = 300.00. There are 2 non-NULL order_value entries. The average is 300.00 / 2 = 150.00.

Example 3:

Input: orders table: (empty)

Output:

NULL

Explanation: When the orders table is empty, there are no values to average, so the result is NULL.

Constraints

The orders table will have at least one column named order_id (integer), customer_id (integer), and order_value (decimal or float type).
The order_value column can contain NULL values.
The query should be efficient and perform well on tables with up to 1 million rows.

Notes

You will be querying a table named orders.
Pseudocode for the relevant SQL function is AVG(column_name).
Consider the data type of the order_value column and how it might affect the precision of the average. The output should generally be a floating-point or decimal number.

Calculate Average Order Value

Problem Description

You need to write an SQL query that calculates the average order_value for all orders in a given table. The query should return a single value representing this average.

Key Requirements:

Calculate the arithmetic mean of the order_value column.
The output should be a single numerical value.

Expected Behavior:

The query should process all rows in the orders table and compute the average of the order_value for each row.

Edge Cases:

Empty Table: If the orders table is empty, what should be returned? (Consider that AVG typically returns NULL for empty sets).
NULL order_value: How should NULL values in the order_value column be handled? (Standard SQL AVG ignores NULL values).

Examples

Example 1:

Input: orders table:

order_id	customer_id	order_value
101	1	50.00
102	2	75.50
103	1	25.00

Output:

60.17

Explanation: The sum of order_value is 50.00 + 75.50 + 25.00 = 150.50. There are 3 orders. The average is 150.50 / 3 = 50.1666... which rounds to 50.17 (assuming typical decimal precision).

Example 2:

Input: orders table:

order_id	customer_id	order_value
201	3	100.00
202	4	NULL
203	3	200.00

Output:

150.00

Example 3:

Input: orders table: (empty)

Output:

NULL

Explanation: When the orders table is empty, there are no values to average, so the result is NULL.

Constraints

The orders table will have at least one column named order_id (integer), customer_id (integer), and order_value (decimal or float type).
The order_value column can contain NULL values.
The query should be efficient and perform well on tables with up to 1 million rows.

Notes

You will be querying a table named orders.
Pseudocode for the relevant SQL function is AVG(column_name).
Consider the data type of the order_value column and how it might affect the precision of the average. The output should generally be a floating-point or decimal number.