通过PHP返回MySQL Count

Question

I have a PHP function that looks like this:

function count_creatives() {
    global $db;
    $q = "SELECT COUNT(DISTINCT creative) FROM actions";
    return $db->query($q);
}

The $db variable contains a PDO object and is set correctly (used successfully elsewhere).

When I try to assign the result of this function to a variable, it only contains the querystring (no results).

Code I'm Running:

$count = count_creatives();

echo $count;

Output:

PDOStatement Object ( [queryString] => SELECT COUNT(DISTINCT creative) FROM actions )

Any idea why I'm not getting the actual count (eg 2, 3, 100)?

Answer 1

PDO::query() returns a PDOStatement object, or FALSE on failure. You need to do something like,

function count_creatives() {
    global $db;
    $q = "SELECT COUNT(DISTINCT creative) FROM actions";
    $query = $db->query($q);
    return $query->fetch(PDO::FETCH_NUM)[0];
}

Answer 2

You're returning the resource object from your function, not the field value. You need to fetch the result and then return that. Please use the following:

function count_creatives() 
{
    global $db;
    $q = "SELECT COUNT(DISTINCT creative) AS `total` FROM actions";
    $result = $db->query($q);
    $actions = $result->fetchObject();

    return $actions->total;
}