PHP记录集返回“错误:查询为空”

我写了以下代码，当它运行时，我得到"错误:查询是空的"无论SQL查询是什么。我知道生成的SQL是好的，因为如果我将它粘贴到SQL数据库中，它会返回行。记录集的PHP代码已经从其他页面粘贴，工作很好，所以我没能看到错误在哪里。

案例4://检查用户是否已经加载了一个检查表

    $mySQL = "SELECT * FROM tools_userChklists WHERE chklistID = '" . $_GET['chklistID'] . "'";
            echo $mySQL;
    $query_rsChecklists = $mySQL;
    $rsChecklists = mysql_query($query_rsChecklists) or die(mysql_error());
    $row_rsChecklists = mysql_fetch_assoc($rsChecklists);
    $totalRows_rsChecklists = mysql_num_rows($rsChecklists);
    if ($totalRows_rsChecklists <> 0){
        //the user has already opened this checklist
        $_SESSION['redirectorAction'] = "";
        $_SESSION['redirectorAction'] = "Location: actions.php?action=5&chklistID=" . $_GET['chklistID'];
    }else{
        //the user has never opened this checklist
        $_SESSION['redirectorAction'] = "";
        $_SESSION['redirectorAction'] = "Location: actions.php?action=6&chklistID=" . $_GET['chklistID'];
    }
break;

任何帮助都是感激的。谢谢。