Cara menulis kueri mysql untuk memeriksa beberapa pilihan variabel di mana pengiriman formulir dapat cocok dengan 1 0f 5 bidang

Saya pribadi tidak pandai melakukan string kueri MySQL, saya biasanya menggunakan kelas kompiler sql yang mirip dengan ini (perlu diingat, ini hanya yang cepat). Ini memungkinkan untuk mengikat, yang Anda butuhkan, terutama dengan $_GET nilai-nilai seperti yang Anda miliki:

class ItemQueue
    {
        protected   $sql;
        protected   $wherevals;
        public      $bind;
        public      $compiled;

        public function select($values = false)
            {
                $this->sql[] = "select";
                if($values == false)
                    $this->sql[]    =   "*";
                else
                    $this->sql[]    =   $values;

                return $this;
            }

        public function from($table = false)
            {
                if($table ==false)
                    return $this;

                $this->sql[] = "from `$table`";

                return $this;
            }

         public function where($values = array(),$op = 'and')
            {
                if(!empty($values)) {
                        $this->sql[]    =   'where';
                        foreach($values as $key => $values) {
                                $this->wherevals[]      =   $key.' = :'.$key;
                                // Bind values for injection protection
                                $this->bind[":$key"]    =   $values;
                            }

                        $this->sql[]        =   implode(" $op ",$this->wherevals);
                        // This part is a bit jenky but you get the idea
                        $this->sql[]        =   "and active = '1'";
                    }

                return $this;
            }

        public  function customsql($values = false)
            {
                if($values != false) {
                        $this->sql[]    =   $values;
                    }

                return $this;
            }

        public  function Fetch()
            {
                // Implode entire sql statement
                $this->compiled =   implode(" ", $this->sql);

                return $this;
            }
    }

    // Post/Get values
    $_POST['cat']   =   'cattest';
    $_POST['city']  =   'Reno';
    $_POST['state'] =   'Nevada';

    // Arbitrary limits
    $limit          =   1;
    $limitvalue     =   1;
    // Create instance
    $tester =   new ItemQueue();
    // Just set some array filtering/validating
    if(isset($_POST['cat']) && !empty($_POST['cat']))
        $array['cat']   =   $_POST['cat'];

    if(isset($_POST['city']) && !empty($_POST['city']))
        $array['city']  =   $_POST['city'];

    if(isset($_POST['state']) && !empty($_POST['state']))
        $array['state'] =   $_POST['state'];

    // Make the query
    $query  =   $tester->select()->from("items")->where($array,"or")->customsql("ORDER BY item_id DESC LIMIT $limitvalue, $limit");

    // Here is the sql statement
    echo $query->Fetch()->compiled;

    // Bind array
    print_r($query->bind);

Memberikan Anda:

select * from `items` where cat = :cat or city = :city or state = :state and active = '1' ORDER BY item_id DESC LIMIT 1, 1

Array
    (
        [:cat] => cattest
        [:city] => Reno
        [:state] => Nevada
    )

Perhatikan, ini mengharuskan Anda untuk menggunakan koneksi yang tepat (PDO berfungsi paling baik dalam kasus ini).