jqgrid表格报错

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'payments' in 'field list'
<?php
require_once '../../../jq-config.php';
// include the jqGrid Class
require_once ABSPATH."php/jqGrid.php";
// include the driver class
require_once ABSPATH."php/jqGridPdo.php";
// Connection to the server
$conn = new PDO(DB_DSN,DB_USER,DB_PASSWORD);
// Tell the db that we use utf-8
$conn->query("SET NAMES utf8");// Create the jqGrid instance
$grid = new jqGridRender($conn);
// Write the SQL Query
$grid->SelectCommand = 'SELECT id,order_id,payments-date FROM `sale_orders`';
// set the ouput format to json
$grid->dataType = 'json';
// Let the grid create the model from SQL query
$grid->setColModel();
// Set the url from where we obtain the data
$grid->setUrl('grid.php');
// Set alternate background using altRows property
$grid->setGridOptions(array(
    "rowNum"=>10,
    "sortname"=>"id",
    "altRows"=>true,
    "multiselect"=>true,
    "rowList"=>array(10,20,50),
    ));
// Change some property of the field(s)
$grid->setColProperty("id", array("label"=>"ID", "width"=>60));
$grid->setColProperty("payments-date", array(
    "formatter"=>"date",
    "formatoptions"=>array("srcformat"=>"Y-m-d H:i:s","newformat"=>"m/d/Y")
    )
);
// Enjoy
$grid->renderGrid('#grid','#pager',true, null, null, true,true);
$conn = null;
?>