What is the difference between the != operator and the NOT operator in PHP when used in SQL queries?

The != operator is used in PHP to check if two values are not equal, while the NOT operator is used in SQL queries to negate a condition. When writing SQL queries in PHP, it's important to use the NOT operator to negate a condition in the WHERE clause, rather than using the != operator which is not valid in SQL. Example PHP code snippet: 

<?php
// Connect to database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// SQL query using NOT operator
$sql = "SELECT * FROM table_name WHERE column_name NOT LIKE '%value%'";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // Output data
    while($row = $result->fetch_assoc()) {
        echo "Column: " . $row["column_name"]. "<br>";
    }
} else {
    echo "0 results";
}

$conn->close();
?>

Keywords

!= operator NOT operator PHP SQL queries difference

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