response.php

<?php
    //include connection file
    include_once("connection.php");

    // initilize all variable
    $params = $columns = $totalRecords = $data = array();

    $params = $_REQUEST;

    //define index of column
    $columns = array(
        0 => '`Full Name`',
        1 => 'Gender',
        2 => 'CityName',
        3 => 'CourseDescriptionLong',
        4 => '`Subject`',
        5 => 'ScholarshipAwarded',
        6 => 'StudentID'
    );

    $where = $sqlTot = $sqlRec = "";

    // check search value exist
    if( !empty($params['search']['value']) ) {
        $where .=" WHERE ";
        $where .=" (`Full Name` LIKE '".$params['search']['value']."%' ";
        $where .=" OR CityName LIKE '".$params['search']['value']."%' ";

        $where .=" OR CourseDescriptionLong LIKE '".$params['search']['value']."%' )";
    }

    // getting total number records without any search
    $sql = "SELECT fullnames.`Full Name`, studentdetails.Gender, lt_cities.CityName, lt_coursedescription.CourseDescriptionLong, lt_coursesubject.`Subject`, Sum(scholarshipdetails.ScholarshipAwarded), studentdetails.StudentID, coursedetails.CourseType, lt_coursedescription.CourseDescriptionShort, scholarshipdetails.ScholarshipYear FROM studentdetails INNER JOIN scholarshipdetails ON studentdetails.StudentID = scholarshipdetails.StudentID INNER JOIN coursedetails ON studentdetails.StudentID = coursedetails.StudentID AND scholarshipdetails.ScholarshipYear = coursedetails.Scholarshipyear LEFT JOIN lt_coursedescription ON coursedetails.CourseID = lt_coursedescription.CourseID INNER JOIN tuitionfeedetails ON studentdetails.StudentID = tuitionfeedetails.StudentID AND scholarshipdetails.ScholarshipYear = tuitionfeedetails.ScholarshipYear INNER JOIN fullnames ON studentdetails.StudentID = fullnames.StudentID INNER JOIN lt_cities ON lt_cities.CityID = studentdetails.City LEFT JOIN lt_coursesubject ON lt_coursesubject.CourseID = lt_coursedescription.CourseID AND lt_coursesubject.SubjectID = coursedetails.CourseSubject GROUP BY studentdetails.StudentID";
    $sqlTot .= $sql;
    $sqlRec .= $sql;
    //concatenate search sql if value exist
    if(isset($where) && $where != '') {

        $sqlTot .= $where;
        $sqlRec .= $where;
    }


    $sqlRec .=  " ORDER BY ". $columns[$params['order'][0]['column']]."   ".$params['order'][0]['dir']."  LIMIT ".$params['start']." ,".$params['length']." ";

    $queryTot = mysqli_query($conn, $sqlTot) or die("database error:". mysqli_error($conn));


    $totalRecords = mysqli_num_rows($queryTot);

    $queryRecords = mysqli_query($conn, $sqlRec) or die("error to fetch employees data");

    //iterate on results row and create new index array of data
    while( $row = mysqli_fetch_row($queryRecords) ) {
        $data[] = $row;
    }

    $json_data = array(
            "draw"            => intval( $params['draw'] ),
            "recordsTotal"    => intval( $totalRecords ),
            "recordsFiltered" => intval($totalRecords),
            "data"            => $data   // total data array
            );

    echo json_encode($json_data);  // send data as json format
?>