执行时间PHP vs MySQL

Question

I have a simple question.

Lets say I have two methods of doing a simple sum of values. I can do it with PHP

foreach($rows as $row)
{
    $total += $row->column;
}

Or I can do it that I can run a query in MySQL database to do the sum

"SELECT sum(column) FROM table";

Which one would finish first. Assuming there are multiple queries already running in a function like

public function abc()
{
      //Query 1 Execution from MySQL
      //Query 2 Execution from MySQL

      //Then comes the "SELECT sum(column) FROM table";
      //OR
      //foreach()
}

Answer 1

Usually the DBMS (in this case mysql) is optimized to do sum and other calculations that outperform a loop in php. In case you have doubts because there are other things that are needed in your script, you can always do this:

$time_start = microtime(true);

// Your code here
.
.
.

$time_end = microtime(true);
$time = $time_end - $time_start;

In the section of your code you can try the different scenarios that you have.