Value from AJAX to PHP using $_POST to update $sql_query - php

Question

I know that this question might have been asked before, but I can't figure it out.
AJAX is passing the selected date to PHP and it should dynamically update this $select with the data from AJAX and update the query made to teh database. But $_POST['date'] seems to be empty and nothing is happening.
AJAX
$(window).ready(function(event) {
var today = new Date();
var dd = today.getDate();
var mm = today.getMonth()+1; //January is 0!
var yyyy = today.getFullYear();
if(dd<10){ dd='0'+dd; }
if(mm<10){ mm='0'+mm; }
var today = yyyy+'-'+mm+'-'+dd; // document.getElementById("DATE").value = today;
selectedDate = today; // selectedDate = '2016-04-17';
var options = {
selectedDate: selectedDate,
onSelectedDateChanged: function(event, date) {
var d = new Date(date);
passDate(d);
}
};
passDate(new Date(selectedDate));
$('#paginator').datepaginator(options);});
function passDate(d) {
date = d.getFullYear() + '-' + (d.getMonth() + 1) + '-' + d.getDate();
console.log(date);
$.ajax({
data: date,
type: "POST",
url: "php/table_body.php"
});};
PHP
<?php
$select = $_POST['data'];
$sql_query="SELECT * FROM users where date = '$select'";
// $sql_query="SELECT * FROM users WHERE date = '2017-05-12'";
$result_set=mysql_query($sql_query);
if(mysql_num_rows($result_set)>0)
{
while($row=mysql_fetch_row($result_set))
{
?>
<tr>
<td><?php echo $row[1]; ?></td>
<td><?php echo $row[2]; ?></td>
<td><?php echo $row[3]; ?></td>
<td><?php echo $row[4]; ?></td>
<td><?php echo $row[5]; ?></td>
<td><?php echo $row[6]; ?></td>
<td><?php echo $row[7]; ?></td>
<td align="center"><span class="glyphicon glyphicon-edit"> Edit</td>
<td align="center"><span class="glyphicon glyphicon-trash"> Delete</td>
</tr>
<?php
}
}
else
{
?>
<tr>
<td colspan="5">No Data Found !</td>
</tr>
<?php
}
Can you help figure how to fix it. Thank you

Answer 1

In the ajax javascript:
data: { date: date },
You didn't define the variable key for the date.
Also change in the php
$select = $_POST['date'];
And as suggested in the comments code for SQL injection protection.

Answer 2

check your parameter on $.ajax for the data, it should be like
$.ajax({
url: "php/table_body.php",
method: "POST",
data: { date: date}
});
for more information visit this link for ajax ref http://api.jquery.com/jquery.ajax/