How can variables be properly managed to avoid overwriting and causing errors in PHP MySQL queries?

To avoid overwriting variables and causing errors in PHP MySQL queries, it's important to use unique variable names for different query components such as the query itself, connection object, result set, etc. Additionally, always sanitize user input to prevent SQL injection attacks and use prepared statements to securely execute queries. 

<?php
// Example of properly managing variables in PHP MySQL queries
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

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

// Example query
$sql = "SELECT * FROM users WHERE id = ?";

// Prepare and bind statement
$stmt = $conn->prepare($sql);
$stmt->bind_param("i", $id);

// Set parameter and execute query
$id = 1;
$stmt->execute();

// Process results
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    echo "Name: " . $row["name"] . "<br>";
}

// Close connection
$stmt->close();
$conn->close();
?>

Keywords

variables PHP MySQL queries error handling data validation

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