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This control flow function that lets you return different values based on a condition inside your SQL query.
MySQL IF() Function
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1. Introduction
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2. Basic Examples
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3. Using IF() with NULL values
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5. Using IF() with Aggregate Functions
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6. Key Differences Between IF() Function and IF Statement
MySQL Conditional Expressions: IF() vs CASE WHENvs IFNULL()
MySQL provides multiple ways to handle conditional logic inside queries. The three most common are:
IF()functionCASE WHENexpressionIFNULL()function
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1. IF() Function
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2. CASE WHEN Expression
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3. IFNULL() Function
4. Side-by-Side Comparison
Feature | IF() | CASE WHEN | IFNULL() |
Conditions | Handles 1 condition (TRUE/FALSE) | Handles multiple conditions | Handles only NULL check |
Syntax | Short & simple | Longer but flexible | Very short |
Readability | Good for simple checks | Best for complex logic | Clean for NULL defaults |
Return type | Any (string/number) | Any (string/number) | Same as expression |
Use case | Quick if-else | Multiple branches | NULL replacement |
5. Practical Scenarios
- Use
IF(): - Use
CASE WHEN: - Use
IFNULL():
When checking a simple TRUE/FALSE condition.
SELECT IF(amount > 10000, 'High Value', 'Normal') AS Value_Category
FROM payments;When checking multiple conditions.
SELECT
CASE
WHEN amount > 20000 THEN 'Very High'
WHEN amount BETWEEN 10000 AND 20000 THEN 'High'
ELSE 'Normal'
END AS Value_Category
FROM payments;When you just want to replace NULL with a default.
SELECT customerName, IFNULL(phone, 'No Phone') AS phone
FROM customers;
✅ In summary:
- Use
IF()for binary conditions. - Use
CASE WHENfor multiple conditional branches. - Use
IFNULL()for handling NULL values.