Php 如何使用select count(*)计算行数

Php 如何使用select count(*)计算行数,php,mysql,json,pdo,Php,Mysql,Json,Pdo,我尝试使用带有多个参数的select count(*)获取行数,并将其编码为JSON格式,但我得到了以下结果: {"notification":[{"count(*)":0}],"message":[{"count(*)":0}]} 除此之外: {"notification":0,"message":0} 此处有页面的代码: session_start(); require_once __DIR__ . '/mysql/Db.class.php'; $bdd = new Db(); $t =

我尝试使用带有多个参数的select count(*)获取行数,并将其编码为JSON格式,但我得到了以下结果:

{"notification":[{"count(*)":0}],"message":[{"count(*)":0}]}
除此之外:

{"notification":0,"message":0}
此处有页面的代码:

session_start();
require_once __DIR__ . '/mysql/Db.class.php';
$bdd = new Db();
$t = array();

$query = $bdd->query("SELECT count(*) FROM notification WHERE id_proprio = :id_proprio AND readed = :readed", array("id_proprio"=> $_SESSION['userid'],"readed"=>"0"));
$query_2 = $bdd->query("SELECT count(*) FROM discussion WHERE id_1 = :uid AND readed = :readed AND notifPour = :uid2 OR id_2 = :uid3 AND readed = :readed2 AND notifPour = :uid4", array(
  "uid"=> $_SESSION['userid'],
  "readed"=>"0",
  "uid2"=> $_SESSION['userid'],
  "uid3"=> $_SESSION['userid'],
  "readed2"=>"0",
  "uid4"=> $_SESSION['userid']
));


$t["notification"] = $query;
$t["message"] = $query_2;

echo json_encode($t);
包括类Db的一部分:

public function query($query,$params = null,$fetchmode = PDO::FETCH_ASSOC)
{
    $query = trim($query);

    $this->Init($query,$params); // INIT IS THE CONNECTION TO DB

    if (stripos($query, 'select') === 0) {
        return $this->sQuery->fetchAll($fetchmode);
    }
    elseif (stripos($query, 'insert') === 0 ||  stripos($query, 'update') === 0 || stripos($query, 'delete') === 0) {
    return $this->sQuery->rowCount(); 
    } else {
        return NULL;
    }
}
如何获得以下例外结果格式:

{"notification":0,"message":0}

谢谢。

您的MySQL API返回所有行的数组,每行都是一个关联数组,其键是
SELECT
子句中的标签。您需要从数组中提取值:

 $t["notification"] = $query[0]['count(*)'];
 $t["message"] = $query_2[0]['count(*)'];

修改SQL查询以开始:

SELECT count(*) AS cnt FROM
然后从查询中提取值,如下所示:

$t["notification"] = $query[0]["cnt"];
$t["message"] = $query2[0]["cnt"];