Question

Cannot write a complete function to compare current month and year to my database m/y. The dates in the database are from the now() function. I want to sum the costs based on this comparison. Something like:

$currentDate = date("Y-m");
$query = mysql_query ("SELECT SUM(cost) FROM memberorders WHERE 
         memberNumber=$memNum AND 
        (SELECT DATE_FORMAT(orderDate, '%Y-%m'))=$currentDate");

But that’s not working. Then I need help with a function to sum it up.

$test1 = mysql_fetch_array($query);
$total = $test1[0];

Would that work for going through the database and summing it up?

Answer 1

Don’t do that, don’t apply any function (like the DATE_FORMAT() function) to a column (like the OrderDate column) if you want indexes to be used. Try this if you can create the fixed starts of months in the application (PHP) code:

SELECT SUM(cost) 
FROM memberorders 
WHERE memberNumber = $memNum 
  AND orderDate >= '2013-01-01'      -- first day of this month
  AND orderDate < '2013-02-01' ;     -- first day of next month

or this if you prefer to handle it in MySQL:

SELECT SUM(cost) 
FROM memberorders 
WHERE memberNumber = $memNum 
  AND orderDate >= LAST_DAY(NOW()) + INTERVAL 1 DAY - INTERVAL 1 MONTH 
  AND orderDate < LAST_DAY(NOW()) + INTERVAL 1 DAY ;