PHP Comparison Operators Explained: ==, ===, <=>, and More

Introduction – Why PHP Comparison Operators Matter

In every PHP application, from login systems to data filters, comparison operators play a crucial role. They determine the truth or falsehood of conditions — such as whether two values are equal or which is larger — allowing developers to make decisions in their code.

Whether you’re building a form validator or sorting product prices, PHP comparison operators are at the core of your logic.

What Are Comparison Operators in PHP?

Comparison operators compare two operands and return a Boolean result (true or false). These operators are mostly used in conditional structures like if, while, and switch.

List of PHP Comparison Operators

Loose vs Strict Comparison

Loose Comparison (==)

PHP tries to convert the data types to match:

var_dump(5 == "5"); // true

5 (integer) and "5" (string) are considered equal because PHP converts both to a common type before comparing.

Strict Comparison (===)

Requires both value and data type to match:

var_dump(5 === "5"); // false

This returns false because although values are the same, the data types differ (int vs string).

Best Practice: Use strict comparison for accurate, secure evaluations, especially in authentication and form validations.

Code Examples with Explanations

1. Equality and Identity

$a = 10;
$b = "10";

var_dump($a == $b);   // true (same value, different types)
var_dump($a === $b);  // false (not same type)

Explanation:

• == compares only values, ignoring data type → returns true.
• === compares both → returns false.

2. Not Equal and Not Identical

$x = 7;
$y = "7";

var_dump($x != $y);   // false (values are equal)
var_dump($x !== $y);  // true (types are not)

Explanation:

• != checks value only.
• !== considers both value and type.

3. Greater Than / Less Than

$a = 8;
$b = 12;

if ($a < $b) {
    echo "$a is less than $b";
}

Output:

8 is less than 12

Explanation:

• $a < $b evaluates to true because 8 is indeed less than 12.

4. Greater Than or Equal To

$score = 90;

if ($score >= 85) {
    echo "You passed!";
}

Output:

You passed!

Explanation:

• The condition checks if score is 85 or more.

5. Spaceship Operator <=>

echo 5 <=> 10; // -1
echo 10 <=> 10; // 0
echo 15 <=> 10; // 1

Explanation:

• -1: Left is less
• 0: Equal
• 1: Left is greater
  Great for custom sorting logic in arrays.

Common Mistakes to Avoid

Mistake 1: Using = instead of ==

if ($value = 5) { echo "Match"; } // always true!

Fix:

if ($value == 5) { echo "Match"; }

Mistake 2: Forgetting data type in security-sensitive checks

$input = "0";

if ($input == false) { echo "False value"; } //  This runs!

Fix:

if ($input === false) { echo "False value"; } //  Type-sensitive

Summary – Recap & Next Steps

PHP comparison operators are essential for building intelligent conditions and control flows in scripts. Misusing them — especially the difference between == and === — can lead to subtle bugs and security flaws.

Key Takeaways:

• Use === and !== for strict, safe comparisons.
• <=> is perfect for sorting and comparison-based logic.
• Avoid = inside if unless you’re assigning on purpose.

Real-World Relevance:
Used in login systems, shopping filters, grade checks, loop exits, and database validations.

Frequently Asked Questions (FAQs)

What is the difference between == and ===?
== checks value only, === checks both value and type.

Is <=> supported in all PHP versions?
No, it was introduced in PHP 7. Not available in PHP 5.

Which is better for secure condition checks — == or ===?
Always use === for type-sensitive or boolean comparisons.

Can I use <> in place of !=?
Yes. They both mean “not equal” in PHP.