PHP - 返回計數（*）結果

Question

如何返回帶有PDO的的計數行數？

這是我的代碼：SELECT count(*) FROM users_notifications WHERE userid=0 OR userid=:userid

Answer 1

的count SQL函數是一個聚合函數：

$n=$dbh->prepare("SELECT count(*) FROM users_notifications WHERE userid=0 OR userid=:userid"); 
$n->bindParam(":userid",$userdata['id']); 
$n->execute(); 
$notifications = count($n); 

當我運行在數據庫中查詢這只是雖然有結果返回1。返回一行，其行數匹配where子句。

PHP的count返回結果集中的行數，如前一段所述，它應該爲1。相反，您應該檢索列的值。例如：

$n=$dbh->prepare("SELECT count(*) as c FROM users_notifications WHERE userid=0 OR userid=:userid"); 
$n->bindParam(":userid",$userdata['id']); 
$n->execute(); 
$result = $n->fetch(PDO::FETCH_ASSOC); 
$notifications = $result['c'];