MySQL IFNULL Simplified: Replace NULL Values in Queries

In MySQL, NULL values can interfere with query results if not handled properly. The IFNULL function allows you to provide a fallback value, helping ensure calculations and outputs behave as expected.

Here’s how to use it and when to choose COALESCE, CASE, or IF instead.

How IFNULL Works

Basic syntax:

IFNULL(value_if_null, value_if_not_null)

SELECT IFNULL(NULL, 'DbVisualizer');  -- returns 'DbVisualizer'

Real-World Example

SELECT product_name, price * (stock_amount + IFNULL(Ordered, 0)) FROM products;

This avoids NULL breaking your math by turning it into zero.

Use COALESCE for More Fallbacks

SELECT COALESCE(NULL, '', 'fallback');  -- returns ''

Good for multi-step defaults.

CASE and IF Also Help

CASE

SELECT CASE WHEN price > 50 THEN 'High' ELSE 'Low' END FROM products;

IF

SELECT IF(price = 0, 'Free', 'Paid') FROM products;

FAQ

What is IFNULL used for?

It replaces NULL values with a default you specify. Ideal for preventing calculation or display errors.

Is IFNULL the same as COALESCE?

Almost. Both handle NULL, but COALESCE can evaluate multiple values. IFNULL is simpler but more limited.

What’s the difference between IFNULL and NULLIF?

IFNULL replaces NULL; NULLIF returns NULL if two values are equal. Their purposes are different.

What are the alternatives to IFNULL in MySQL?

Use COALESCE for more fallbacks, CASE for condition trees, and IF for binary logic checks.

Conclusion

IFNULL is a go-to tool when dealing with NULL in MySQL. It simplifies logic and helps prevent errors in calculations and display.

When your logic gets more complex, consider COALESCE, CASE, or IF. Each has a place in writing clear and flexible SQL.

See more examples in the full article MySQL IFNULL - Everything You Need to Know.