While loop inside foreach loop not proceeding to foreach loop

Question

I am storing dates from a query to an array by using while loop and array_push.

$h = array();
$j = array();

while ($g = mysql_fetch_array($f)) {
   $date = new DateTime($g['selected_date']);
   echo "<th>" . date_format($date, 'd') . "</th>";
   array_push($h, $date);
   array_push($j, $g['selected_date']);
}

Printing that array returns to this which is fine, I think.

Array (
   [0] => 2016-05-23
   [1] => 2016-05-24
   [2] => 2016-05-25
   [3] => 2016-05-26
   [4] => 2016-05-27
   [5] => 2016-05-28
)

I try to use like this:

$a = mysql_query("select * from center") or die(mysql_error());
$arr = array();

foreach($j as $k) {
    while ($b = mysql_fetch_array($a)) {
        $l = "select sum(yid.center_inventory) as 'total' 
              from yl_inventory_details as yid
              left join yl_inventory as yi 
                  on yi.yl_inventory_no = yid.yl_inventory_no
              where yid.center_no = '$b[center_no]'
              and yi.date = '$k'";
        $c = mysql_query("$l") or die(mysql_error());
        $d = mysql_fetch_array($c);
        echo "<tr><td>".$b['center']."</td><td>".$d['total']."</td></tr>";              
    }
}

But it only takes the first value which is 2016-05-23 . The while loop doesn't seem to proceed to the next foreach value. How can I fix this?

Answer 1

When you use mysql_fetch_array it shifts onto the next row in the result. Once you reach the last result, it starts returning FALSE .

To make your code work, all you have to do is swap the loops the other way round.

Eg

$a = mysql_query("select * from center") or die(mysql_error());
$arr = array();
while ($b = mysql_fetch_array($a))
{
    foreach($j as $k)
    {
            $l = "select
                    sum(yid.center_inventory) as total 
                from yl_inventory_details as yid
                left join yl_inventory as yi on yi.yl_inventory_no = yid.yl_inventory_no
                where yid.center_no = {$b['center_no']} and yi.date = {$k}";
            $c = mysql_query($l) or die(mysql_error());
            $d = mysql_fetch_array($c);
            echo
            "<tr>
                <td>{$b['center']}</td>
                <td>{$d['total']}</td>
            </tr>";             
    }
}