What are common issues when using MySQL queries in PHP scripts?

One common issue when using MySQL queries in PHP scripts is SQL injection attacks. To prevent this, you should always use prepared statements with parameterized queries instead of directly inserting user input into your SQL queries. Example PHP code snippet using prepared statements: 

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

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

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

// Set the parameter values and execute the query
$username = "john_doe";
$stmt->execute();

// Bind the result variables and fetch the results
$stmt->bind_result($id, $username, $email);
$stmt->fetch();

// Display the results
echo "User ID: $id, Username: $username, Email: $email";

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

Keywords

MySQL PHP queries errors troubleshooting

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