php – 为什么搜索查询没有在PHRETS中显示任何结果？

我已经下载了属性here的元数据excel文件

$rets_login_url = "http://sef.rets.interealty.com/Login.asmx/Login";
$rets_username = "xxxxxxxx";
$rets_password = "xxxxxxxx";
$rets_user_agent = "PHRETS/1.0";
$rets_user_agent_password = "xxxxxxx";

//////////////////////////////

// start rets connection
$rets = new phRETS;
// Uncomment and change the following if you're connecting
// to a server that supports a version other than RETS 1.5

$rets->AddHeader("RETS-Version","RETS/1.5");

$rets->AddHeader("User-Agent",$rets_user_agent);

echo "+ Connecting to {$rets_login_url} as {$rets_username}<br>n";
$connect = $rets->Connect($rets_login_url,$rets_username,$rets_password,$rets_user_agent_password);

// check for errors
if ($connect) {
        echo "  + Connected<br>n";
}
else {
        echo "  + Not connected:<br>n";
        print_r($rets->Error());
        exit;
}

$search = $rets->SearchQuery("Property","ResidentialProperty","(ListDate=1990-01-01+)");
while ($listing = $rets->FetchRow($search)) {
   echo "Address: {$listing['StreetNumber']} {$listing['StreetName']},";
   echo "{$listing['City']},";
   echo "{$listing['State']} {$listing['ZipCode']} listed for ";
   echo "$".number_format($listing['ListPrice'])."n";
}


$rets->FreeResult($search);

echo "+ Disconnecting<br>n";
$rets->Disconnect();

当我运行此脚本时,它显示连接的结果,然后断开连接.但没有找到结果.我试了很多关于结果没有显示的问题的建议,但没有什么对我有用.哪里错了？

我的RETS服务器信息在这里：

RETS服务器：SEF RETS系统
RETS系统ID：SEFRETS
登录URL：http://sef.rets.interealty.com:80/Login.asmx/Login
RETS版本：1.5
服务器软件：Microsoft-IIS / 6.0

我也无法理解什么是$rets_modtimestamp_field =“LIST_87”;

请帮我.我需要一些关于如何从RETS获取数据的建议.