Average by Category SQL Query | Dataford Interview Questions

Write a SQL query to calculate the average value of a column grouped by category.

Use the category_values table. Include a NULL category as its own group, ignore NULL values when calculating averages, and sort categories alphabetically with the NULL category last.

Output

One row per category, including the NULL category.
Columns: category and average_value.
Sort by category ascending, with NULL last.

Schema

category_values

Column	Type	Description
value_idPK	INT	Unique identifier for the value record
category	VARCHAR(50)	Category assigned to the value
value	NUMERIC(10,2)	Numeric value to average

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