Combination of field search using PHP & MYSQL

Question

I am working on an assignment using PHP & MYSQL.

one of the tasks is to search on any combination of the fields. That includes Dropdown boxes populated from the

Answer 1

I've done something similar in the past where I checked the value from different fields and then added them to a series of arrays. I created an array for select, from, where, order. You can do similar for other sets like group or limit. Then I ran 'array_unique', imploded them and put them into the SQL string.

$array_select = array('users.Id'); // SET SOME DEFAULTS SO THE QUERY WILL ALWAYS RUN
$array_from = array('users');
$array_where = array();
$array_order = array();

if (isset($first_name)) {
    $array_select[] = 'First_Name';
    $array_from[] = 'users';
}

if (isset($city)) {
    $array_select[] = 'City';
    $array_from[] = 'user_contact';
    $array_where[] = 'users.Id = user_contact.City';
}

if ($array_select) {
    $array_select = array_unique($array_select);
    $string_select = implode(', ', $array_select);
}
if ($array_where) {
    $array_where = array_unique($array_where);
    $string_where = 'WHERE '.implode(' AND ', $array_where);
}
// REPEAT FOR OTHERS ...



// BUILD THE QUERY OUT
$sql = 'SELECT '.$string_select.' FROM '.$string_from.' '.$string_where.' ...

Answer 2

Why not evaluate your string with each column (this is a guide only, I'm not building your PHP code there:

SELECT 
  * 
FROM 
  table
WHERE 
  (ID = $id OR $id = 'showAll')
  AND (SPORT = $sport OR $sport = 'showAll')
  AND (COUNTRY = $country OR $country = 'showAll')
  AND (GENDER = $gender OR $gender = 'showAll')
  AND (FIRSTNAME = $firstname OR $firstname = 'showAll')

Just need to make sure you NVL the variables to an appropriate value (whether it be int or string)

Answer 3

Instead of all those conditionals about whether to add AND when concatenating to the query, use an array and implode.

$fields = array('sport' => 'sport',
                'gender' => 'gender', 
                'fname' => 'firstName',
                'lname' => 'lastName',
                'country' => 'country');
$wheres = array();
foreach ($fields as $postfield => $dbfield) {
    if ($_POST[$postfield] != 'showAll') {
        $wheres[] = "$dbfield = '" . mysql_real_escape_string($_POST[$postfield]) . "'";
    }
}
$selectString = "SELECT t2ath.lastName, t2ath.firstName, t2ath.image, t2ath.sport, t2ath.gender, t2ath.country, t2country.flag 
                 FROM t2ath LEFT JOIN t2country
                 ON t2ath.country = t2country.name";
if (count($wheres) > 0) {
    $selectString .= " WHERE " . implode(" AND ", $wheres);
}
$result = mysql_query($selectString);

To see how to do it similarly using PDO prepared statements, see my answer here: What code approach would let users apply three optional variables in PHP/MySQL?