How can PHP developers effectively test and troubleshoot SQL queries before integrating them into their code to prevent errors like "Supplied argument is not a valid MySQL result resource"?

When testing and troubleshooting SQL queries in PHP, developers can use functions like `mysqli_query()` to execute the query and check for errors before integrating it into their code. By checking the return value of `mysqli_query()` and handling any errors that may arise, developers can prevent issues like "Supplied argument is not a valid MySQL result resource".

// Example of testing and troubleshooting SQL queries in PHP
$query = "SELECT * FROM users";
$result = mysqli_query($connection, $query);

if (!$result) {
    die("Error executing query: " . mysqli_error($connection));
}

// Use the $result object in further processing