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SQL AVG Function

Quick summary: The SQL AVG() function returns the average value of a numeric column.

SQL AVG Syntax 

SELECT AVG(column_name) FROM table_name WHERE condition
SQL

SQL AVG Basic examples 

SELECT AVG(price) FROM products;
SQL
Output:
Average product price

Calculates the mean value.

SQL AVG Real-world usage 

SELECT AVG(total) FROM orders WHERE status = 'paid';
SQL
Output:
Average order value

Used for analytics.

SQL AVG Edge cases 

SELECT AVG(price) FROM products WHERE category_id = 999;
SQL
Output:
NULL

Returns NULL when no rows match.

SQL AVG Common mistakes

Averaging integers without casting

Some databases may return integer division.

Incorrect
AVG(quantity)
Correct
AVG(quantity * 1.0)

Ensure floating-point arithmetic.

SQL AVG Frequently Asked Questions

What does AVG() do in SQL?

Calculates the average value of a column.

Use case of AVG()?

Mean calculations.

Handles NULL?

Ignores NULL values.

Return type?

Numeric (float).

Common mistake?

Expecting integer result.

Works with GROUP BY?

Yes.

Supports DISTINCT?

Yes.

Performance?

Efficient.

Used in analytics?

Yes.

Alternative?

SUM()/COUNT().

Handles decimals?

Yes.

Best practice?

Check precision.

SQL AVG Related SQL Keywords