具有SUM（）的PDO :: FETCH_ASSOC无法正常工作？

Question

Why doesn't this work?

$selectAllCount = $db->prepare("SELECT SUM(`count`) FROM `Test_Table`");
$selectAllCount->execute();

while($allCountRow = $selectAllCount->fetch(PDO::FETCH_ASSOC)) {
    echo $allCountRow['count'];
}

I have tried many other methods with mysql_libs and none of them seem to work, what's wrong here?

Answer 1

Make sure to give the column a name:

$selectAllCount = $db->prepare("SELECT SUM(`count`) as count FROM `Test_Table`");

Now you'll be able to fetch the result as you wanted.

Answer 2

This seems to be the best way:

$selectAllCount = $db->prepare("SELECT SUM(`count`) FROM `Test_Table`");
$selectAllCount->execute();
$count = $selectAllCount->fetchColumn(0);

Documentation: http://php.net/manual/en/pdostatement.fetchcolumn.php