How can PHP syntax errors be identified and resolved when working with complex queries?

PHP syntax errors can be identified and resolved when working with complex queries by carefully reviewing the code for any missing or misplaced punctuation, such as semicolons, parentheses, or quotes. Using an integrated development environment (IDE) with syntax highlighting can also help pinpoint errors. Additionally, utilizing tools like PHP linters or running the code through a syntax checker can assist in quickly identifying and fixing syntax errors.

$query = "SELECT * FROM users WHERE id = $user_id";
$result = mysqli_query($connection, $query);

if ($result) {
    while ($row = mysqli_fetch_assoc($result)) {
        echo "User ID: " . $row['id'] . " | Username: " . $row['username'] . "<br>";
    }
} else {
    echo "Error: " . mysqli_error($connection);
}