Datatables Filter not working when applying SQL Server 2008 pagination code

I have managed to make the pagination work (thanks to @zhorov) but somehow it’s conflicting with the search/filter function.

Tried to put each query in each $_post to see if the select query will not conflict and when I put the first select query at the bottom it will override the query for pagination. When I put the pagination query on top it wont display anything.

Here is the complete code that I have

`<?php

include('db.php');
include('function.php');
$query = '';
$output = array();
$query .= "SELECT * FROM users ";
if(isset($_POST["search"]["value"]))
{

    $query .= "WHERE emp_id LIKE '%".$_POST["search"]["value"]."%'  ";
    $query .= "OR id LIKE '%".$_POST["search"]["value"]."%'  ";

}
if(isset($_POST["order"]))
{
    $query .= "ORDER BY ".$_POST['order']['0']['column']." ".$_POST['order']['0']['dir']." ";
}
else
{
    $query .= "ORDER BY id DESC ";
}
if ($_POST["length"] != -1)
 {

     $query = "SELECT *
        FROM (
            SELECT 
                *, 
                ROW_NUMBER() OVER (ORDER BY id DESC) AS Rn
            FROM users )";
    $query .=         
        "sub WHERE  status = 'Active' AND Rn BETWEEN ".($_POST["start"])." AND ".($_POST["start"]  + $_POST["length"] - 1 );        
}

 $menu="";
$statement = $connection->prepare($query);
$statement->execute();
$result = $statement->fetchAll();
$data = array();
$filtered_rows = $statement->rowCount();
foreach($result as $row)
{

    $sub_array = array();
    $sub_array[] = $row['id'];
    $sub_array[] = $row['emp_id'];
    $sub_array[] = $row['username'];
    $sub_array[] = $row['password'];
    $sub_array[] = $row['email'];
    $sub_array[] = $row['firstname'];
    $sub_array[] = $row['middlename'];
    $sub_array[] = $row['lastname'];
    $sub_array[] = $row['location'];
    $sub_array[] = $row['contact_no'];
    $sub_array[] = $row['gender'];
    $sub_array[] = $row['access_type'];
    $sub_array[] = $row['status'];
    $sub_array[] = $row['date_reg'];    
        $sub_array[] = '<button type="button" name="update" id="'.$row["id"].'" class="btn btn-warning btn-xs update">Deactivate</button>';
    $data[] = $sub_array;
}
$output = array(
    "draw"              =>  intval($_POST["draw"]),
    "recordsTotal"      =>  $filtered_rows,
    "recordsFiltered"   =>  get_total_all_records(),
    "data"              =>  $data
);
echo json_encode($output);
?>`

Both the Pagination and Filter/Serch should work.

Answer

It’s probably too late for this answer, but I think that next approach may help. You just need to put your WHERE clause in the subquery.

<?php

...
# WHERE clause
$where = "WHERE (status = 'Active') ";
if (isset($_POST["search"]["value"])) {
    $where .= " AND ((emp_id LIKE '%".$_POST["search"]["value"]."%') OR (id LIKE '%".$_POST["search"]["value"]."%')) ";
}

# Whole statement
if ($_POST["length"] != -1) {
     $query = "SELECT *
        FROM (
            SELECT 
                *, 
                ROW_NUMBER() OVER (ORDER BY id DESC) AS Rn
            FROM users ".$where." ) ";
    $query .=         
        "sub WHERE Rn BETWEEN ".($_POST["start"])." AND ".($_POST["start"]  + $_POST["length"] - 1 );        
}
if (isset($_POST["order"])) {
    $query .= " ORDER BY ".$_POST['order']['0']['column']." ".$_POST['order']['0']['dir']." ";
} else {
    $query .= " ORDER BY id DESC ";
}
...

?>

Notes:

This example is based on your code. Note, that although you use prepared statements ($connection->prepare($query)), it’s necessery to use parameters to prevent SQL injection, when you have user input.