How can PHP developers effectively prevent SQL injection vulnerabilities when querying a MySQL database?

SQL injection vulnerabilities can be prevented by using prepared statements with parameterized queries in PHP when querying a MySQL database. This approach helps separate SQL code from user input, making it impossible for malicious input to alter the SQL query structure. 

// Establish a connection to the MySQL database
$mysqli = new mysqli("localhost", "username", "password", "database");

// Prepare a SQL statement with a parameterized query
$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");

// Bind parameters to the prepared statement
$stmt->bind_param("s", $username);

// Set the parameter values
$username = $_POST['username'];

// Execute the prepared statement
$stmt->execute();

// Process the results
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    // Do something with the data
}

// Close the statement and connection
$stmt->close();
$mysqli->close();

Keywords

PHP SQL injection MySQL prepared statements parameterized queries

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