jqgrid报表报错

jqgrid表格报错
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'payments' in 'field list'

<br />
<?php<br />
require_once '../../../jq-config.php';<br />
// include the jqGrid Class<br />
require_once ABSPATH."php/jqGrid.php";<br />
// include the driver class<br />
require_once ABSPATH."php/jqGridPdo.php";<br />
// Connection to the server<br />
$conn = new PDO(DB_DSN,DB_USER,DB_PASSWORD);<br />
// Tell the db that we use utf-8<br />
$conn->query("SET NAMES utf8");<br />
<br />
// Create the jqGrid instance<br />
$grid = new jqGridRender($conn);<br />
// Write the SQL Query<br />
$grid->SelectCommand = 'SELECT id,order_id,payments-date FROM `sale_orders`';<br />
// set the ouput format to json<br />
$grid->dataType = 'json';<br />
// Let the grid create the model from SQL query<br />
$grid->setColModel();<br />
// Set the url from where we obtain the data<br />
$grid->setUrl('grid.php');<br />
// Set alternate background using altRows property<br />
$grid->setGridOptions(array(<br />
    "rowNum"=>10,<br />
    "sortname"=>"id",<br />
    "altRows"=>true,<br />
    "multiselect"=>true,<br />
    "rowList"=>array(10,20,50),<br />
    ));<br />
// Change some property of the field(s)<br />
$grid->setColProperty("id", array("label"=>"ID", "width"=>60));<br />
$grid->setColProperty("payments-date", array(<br />
    "formatter"=>"date",<br />
    "formatoptions"=>array("srcformat"=>"Y-m-d H:i:s","newformat"=>"m/d/Y")<br />
    )<br />
);<br />
// Enjoy<br />
$grid->renderGrid('#grid','#pager',true, null, null, true,true);<br />
$conn = null;<br />
?><br />

------解决方案--------------------
字段名是 payments-date 吗？中间有减号？
`payments-date`