Searching the database for many parameters php jquery ajax

Try this code.

 <?php
    //parameters
    $First_Name="val1";
    $Last_Name="val2";
    $Address="val3";
    $Valid_ID="";
    $Age="val5";
    $Gender="val6";
    $Dob="val7";
    //push the parameter names to array
    $parms=array("First_Name","Last_Name","Address","Valid_ID","Age","Gender","Dob");
    //iterate parameter name
    foreach($parms as $s){
        //check whether the parameter value is not empty
         if(!empty(${$s})){
            //your sql where condition
          echo $s.'='.${$s}."<br>"; //here it will print only non empty param and values
          }
    }
 ?>

Write select query in a variable then append it with where conditions like given below then append (and/or) key word until before last parameter.

   $qry="select * from table where ";
    $i=0;
    $paramcount=0;
     $cond=array(); //condition paramters
    foreach($parms as $c){
         if(!empty(${$c})){
             $paramcount++; //non empty parameters count
             $cond[]= $c.'="'.${$c}.'"';    //condition parameters 
      }
    }
    foreach($cond as $s){
        if($i<$paramcount-1){
        $qry=$qry.$s." and "; //appending add/or keyword with sql query
    }
    else{
        $qry=$qry.$s; //if last parameter means append parameter without and/or keyword
    }
        $i++;
    }

   echo "Final Query is --><br> ".$qry;

Do you really need to control each combination state. If so using flag variables, bitwise operators and case statement can be more handy. Even so i recommend to change your algoritm. Using something more flexible. Such as developing a class handles all the logic, setting all params a default value and creating the SQL Query string dynamically.

Here is my code from a project similiar to yours. I was used DB Query Builder class on laravel.

class recSQL {

    protected $recFinder;

    // $search_criteria is an instance of a class that 
    // contains default paramaters and overriden by user input parameters

    public function findRec($search_criteria, $sort_criteria)
    {
        $this->recFinder = DB::table('myTable')
            ->join('users', 'recs.user_id', '=', 'users.id')
            ->join('placelar', 'recs.place_id', '=', 'placelar.id')
            ->join('nested_categoris', 'recs.cat_id', '=', 'category.id')
            ->select(   'recs.user_id', 
                        'users.name as user_name',
                        'recs.id', 
                        'recs.baslik', 
                        'recs.price', 
                        'recs.durum_id', 
                        'category.name as category_name',
                        'recs.updated_at as date',
                        'placelar.ad as place');
        $this->applySearchCriteria($search_criteria);
        $this->applySortCriteria($sort_criteria);
        return $this->recFinder->paginate(3);
    }



    protected function applySearchCriteria($search_criteria)
        {
            // the parameters that allways in query
            $this->recFinder->where('recs.price', '<', $search_criteria->max_price());
            $this->recFinder->where('recs.price', '>', $search_criteria->min_price());
            $this->recFinder->where('recs.durum_id', '=', $search_criteria->durum());
            // the parameters if exists add to query
            if($search_criteria->place()) {
               $this->recFinder->where('recs.place_id','=', $search_criteria->place());}
            if($search_criteria->size()) {
               $this->recFinder->where('recs.size_id','=', $search_criteria->size());}
            if ($search_criteria->category()>0) {
                $secilen_category = Nestedcategory::where('id',$search_criteria->category())->first();
                $this->recFinder->where('category.lft','>=' , $secilen_category->lft);
                $this->recFinder->where('category.rgt','<=' , $secilen_category->rgt);
            }
        }



    protected function applySortCriteria($sort_criteria)
        {
            switch ($sort_criteria)
            {
                case Sirala::$dateasc:
                    $this->recFinder->orderBy('recs.updated_at', 'asc');
                    break;
                case Sirala::$datedesc:
                    $this->recFinder->orderBy('recs.updated_at', 'desc');
                    break;
                case Sirala::$priceasc:
                    $this->recFinder->orderBy('recs.price', 'asc');
                    break;
                case Sirala::$pricedesc:
                    $this->recFinder->orderBy('recs.price', 'desc');
                    break;
                // default:
                   // handle error;
            }
        }

}

I wish this helps you.