Search Filtering with PHP/MySQL

Question

I\'m trying to create a search/filtering option in my blood donor application. Where donor can be searched by sex, name, blood group or by selecting all three. Here is my code

Answer 1

function search_donar($_POST) {

    $by_name = $_POST['by_name'];
    $by_sex = $_POST['by_sex'];
    $by_group = $_POST['by_group'];
    $by_level = $_POST['by_level'];

    $search_query = "SELECT * FROM donar WHERE";

    $and = '';
    if(count($_POST) > 1) {
        $and ='AND';
    }
    if($_POST[0]) {
        $and ='';
    }

    if($by_name !="") {
        $search_query .= $and." name='$by_name'";
    }
    if($by_sex !="") {
        $search_query .= $and." sex='$by_sex'";
    }
    if($by_group !="") {
        $search_query .= $and." blood_group='$by_group'";
    }
    if($by_level !="") {
        $search_query .= $and." e_level='$by_level'";
    }

    if(count($_POST) == 0) {
        $search_query .= " 1 ";
    }

    $search_query;
    $result = mysql_query($search_query);

    return $result;
}