Parameter value is not sending from jquery.ajax to sql query

Parameter value is not sending from jquery.ajax to sql query

Hi,
I tried to send some parameters value to sql query from jqury.ajax, But the parameter value is not getting in sql query. Below is my code

        $.ajax({
            type: 'POST',
            url: 'query.php',
            dataType: 'json',
            data: {
                dayNo: "2",
                event_id:"4",
              
            },
           
            success: function (data) {
               
                var items = [];
                for (var i = 0; i < data.length; i++) {
                    var row = data[i]
                    items.push({
                        thermeName: row[3],
                        sessionTime: row[4],
                        sessionTopic: row[5]
                    });
                }
                viewModel.listItems(items);
            }
        });



And this is my sql Query in query.php file

$query = "SELECT id,event_id,dayNo,themeName,sessionTime,sessionTopic from agenda WHERE event_id= '+event_id+' AND dayNo='+dayNo+'";


Thanks in Advance