How can PHP developers optimize their code to execute SELECT and UPDATE queries separately when dealing with limitations in MySQL subqueries?

When dealing with limitations in MySQL subqueries, PHP developers can optimize their code by executing SELECT and UPDATE queries separately. This involves first fetching the necessary data with a SELECT query, processing it in PHP, and then using the obtained values to construct and execute an UPDATE query. By separating the SELECT and UPDATE operations, developers can work around the limitations of MySQL subqueries and ensure efficient and effective data manipulation.

// Execute SELECT query to fetch necessary data
$selectQuery = "SELECT id, column1, column2 FROM table WHERE condition = 'value'";
$result = mysqli_query($connection, $selectQuery);

if ($result) {
    while ($row = mysqli_fetch_assoc($result)) {
        // Process data as needed
        $id = $row['id'];
        $newValue = $row['column1'] + $row['column2'];

        // Construct and execute UPDATE query
        $updateQuery = "UPDATE table SET column3 = '$newValue' WHERE id = $id";
        mysqli_query($connection, $updateQuery);
    }
}