功能错误（致命错误：函数名称必须是字符串）

Question

<?php
    require_once('includes/auth.php');
    function getMarkets(){
        $count_markets=querydb("SELECT count(*) as marketcount from markets ");
        $result=$count_markets('marketcount');
        return $result;
    }

我有上面的代码，我收到以下错误：
致命错误：函数名称必须是字符串

Answer 1

看到错误正在使用$count_markets('marketcount');而不是$count_markets['marketcount'];

Answer 2

$result=$count_markets('marketcount'); - 从$移除count_markets。