Datatables serverside Select row WHERE

Question

I am using Datatables to display a list of all registered users in my sql database. I am using the serverside php code provided on datatables.net website (provided below) what I need to do is create a datatable that displays all users only if they are listed as Male In the Gender Column. Normally with php i would do the following:

SELECT * FROM users WHERE Gender = Male

But for the life of me I can not work out how to do this with datatables. Here is he datatables serverside code:

/*
 * Script:    DataTables server-side script for PHP and MySQL
 * Copyright: 2010 - Allan Jardine
 * License:   GPL v2 or BSD (3-point)
 */

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Easy set variables
 */

/* Array of database columns which should be read and sent back to DataTables. Use a space where
 * you want to insert a non-database field (for example a counter or static image)
 */
$aColumns = array( 'FName', 'LName', 'Gender', 'Email');

/* Indexed column (used for fast and accurate table cardinality) */
$sIndexColumn = "id";

/* DB table to use */
$sTable = "users";

/* Database connection information */
$gaSql['user']       = "";
$gaSql['password']   = "";
$gaSql['db']         = "";
$gaSql['server']     = "localhost";


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * If you just want to use the basic configuration for DataTables with PHP server-side, there is
 * no need to edit below this line
 */

/*
 * Local functions
 */
function fatal_error ( $sErrorMessage = '' )
{
    header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
    die( $sErrorMessage );
}

/*
 * MySQL connection
 */
if ( ! $gaSql['link'] = mysql_pconnect( $gaSql['server'], $gaSql['user'], $gaSql['password']  ) )
{
    fatal_error( 'Could not open connection to server' );
}

if ( ! mysql_select_db( $gaSql['db'], $gaSql['link'] ) )
{
    fatal_error( 'Could not select database ' );
}

/*
 * Paging
 */
$sLimit = "";
if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' )
{
    $sLimit = "LIMIT ".intval( $_GET['iDisplayStart'] ).", ".
        intval( $_GET['iDisplayLength'] );
}

/*
 * Ordering
 */
if ( isset( $_GET['iSortCol_0'] ) )
{
    $sOrder = "ORDER BY  ";
    for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ )
    {
        if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" )
        {
            $sOrder .= $aColumns[ intval( $_GET['iSortCol_'.$i] ) ]."
                ".($_GET['sSortDir_'.$i]==='asc' ? 'asc' : 'desc').", ";
        }
    }

    $sOrder = substr_replace( $sOrder, "", -2 );
    if ( $sOrder == "ORDER BY" )
    {
        $sOrder = "";
    }
}

/*
 * Filtering
 * NOTE this does not match the built-in DataTables filtering which does it
 * word by word on any field. It's possible to do here, but concerned about efficiency
 * on very large tables, and MySQL's regex functionality is very limited
 */
$sWhere = "";
if ( $_GET['sSearch'] != "" )
{
    $sWhere = "WHERE (";
    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" )
        {
            $sWhere .= $aColumns[$i]." LIKE '%".mysql_real_escape_string( $_GET['sSearch'] )."%' OR ";
        }
    }
    $sWhere = substr_replace( $sWhere, "", -3 );
    $sWhere .= ')';
}

/* Individual column filtering */
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
    if ( $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' )
    {
        if ( $sWhere == "" )
        {
            $sWhere = "WHERE ";
        }
        else
        {
            $sWhere .= " AND ";
        }
        $sWhere .= $aColumns[$i]." LIKE '%".mysql_real_escape_string($_GET['sSearch_'.$i])."%' ";
    }
}

/*
 * SQL queries
 * Get data to display
 */
$sQuery = "
    SELECT SQL_CALC_FOUND_ROWS ".str_replace(" , ", " ", implode(", ", $aColumns))."
    FROM   $sTable
    $sWhere 
    $sOrder
    $sLimit
";
$rResult = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );

/* Data set length after filtering */
$sQuery = "
    SELECT FOUND_ROWS()
";
$rResultFilterTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
$aResultFilterTotal = mysql_fetch_array($rResultFilterTotal);
$iFilteredTotal = $aResultFilterTotal[0];

/* Total data set length */
$sQuery = "
    SELECT COUNT(".$sIndexColumn.")
    FROM   $sTable
";
$rResultTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
$aResultTotal = mysql_fetch_array($rResultTotal);
$iTotal = $aResultTotal[0];


/*
 * Output
 */
$sOutput = '{';
$sOutput .= '"sEcho": '.intval($_GET['sEcho']).', ';
$sOutput .= '"iTotalRecords": '.$iTotal.', ';
$sOutput .= '"iTotalDisplayRecords": '.$iFilteredTotal.', ';
$sOutput .= '"aaData": [ ';
while ( $aRow = mysql_fetch_array( $rResult ) )
{
    $sOutput .= "[";
    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        if ( $aColumns[$i] == "version" )
        {
            /* Special output formatting for 'version' */
            $sOutput .= ($aRow[ $aColumns[$i] ]=="0") ?
                '"-",' :
                '"'.str_replace('"', '\"', $aRow[ $aColumns[$i] ]).'",';
        }
        else if ( $aColumns[$i] != ' ' )
        {
            /* General output */
            $sOutput .= '"'.str_replace(
                array( '"', "\n", "\r" ),
                array( '\\"', "\\n", "\\n"),
                $aRow[ $aColumns[$i] ] ).'",';
        }
    }

    /*
     * Optional Configuration:
     * If you need to add any extra columns (add/edit/delete etc) to the table, that aren't in the
     * database - you can do it here
     */

    $sOutput = substr_replace( $sOutput, "", -1 );
    $sOutput .= "],";
}
$sOutput = substr_replace( $sOutput, "", -1 );
$sOutput .= '] }';

echo $sOutput;

Answer 1

You can modify either the filtering section beginning:

$sWhere = "";

or the actual query creation further down:

$sQuery = "
SELECT SQL_CALC_FOUND_ROWS ".str_replace(" , ", " ", implode(", ", $aColumns))."
FROM   $sTable
$sWhere 
$sOrder
$sLimit
";

In either case, the issue is if you use any additional filtering within datatables then accounting for the and/or to build the where can break it.

In my case, I removed the line in filtering which closes the where and then before running the actual $sQuery checked if $sWhere=="" and had two different queries depending on which outcome (one with $sWhere and one without) but both with my where and then manually added the closing bracket to the query.

From memory I used something like the below (not tested so may need tweaked):

if ($sWhere=="") {
    $sQuery = "
        SELECT SQL_CALC_FOUND_ROWS ".str_replace(" , ", " ", implode(", ", $aColumns))."
        FROM   $sTable
        Where Gender='Male' 
        $sOrder
        $sLimit
    ";
} else {
    $sQuery = "
        SELECT SQL_CALC_FOUND_ROWS ".str_replace(" , ", " ", implode(", ", $aColumns))."
        FROM   $sTable
        $sWhere AND Gender='Male'".)." 
        $sOrder
        $sLimit
        ";
}

There may be a better way of doing this but it worked for me.