code for fetching value to select option

Question

I have select option. this option has multiple value from database. I want to update something from database, this value i want to update is exist on the select option I have.

this is my option code

  $id = $_GET['update'];

        $query = mysql_query("SELECT * FROM transaction where id = '$id'") or die ("could not search");
        $count = mysql_num_rows($query);    

        while ($rows = mysql_fetch_array($query)) {

        $id = $rows['id'];
        $tranid = $rows['tranid'];
        $trandate = $rows['trandate'];
        $patientid = $rows['patientid'];
        $transactiontype = $rows['transactiontype'];
        $trandescription = $rows['trandescription'];
        $tranquantity = $rows['tranquantity'];
        $tranunitprice = $rows['tranunitprice'];
        $tranamount =$rows['tranamount'];
        $gettrandescription = $rows['trandescription'];

        }
        }

        if (isset($_POST['selectmedicine'])) {

        $gettrandescription=$_POST['medicineid'];   
        }

        if (isset($_POST['selectroomquantity'])) {

        $tranquantity=$_POST['quantity'];
        }

        ?>
        <script type="text/javascript">
        $('#collapseone').collapseone({
        toggle: true
        });

    <option value="<?php echo $trandescription; ?>" <?php    if($trandescription==$gettrandescription){ echo "selected";} ?> ><?php echo $gettrandescription; ?></option>
    <option value="<?php echo $tranquantity; ?>" <?php if($tranquantity==$tranquantity){ echo "selected";} ?> ><?php echo $tranquantity; ?></option>

this has value results, but i cant fetch this value to my existing select option.

Answer 1

If you want to "make that variable an array" as aldrin27 said, append [] to the name attribute of the select tag. The selected value of the option with name selectroomquantity will be available in your script as $_POST["selectroomquantity"] (this is the varible).

<select multiple name="selectroomquantity[]">
    <option value="...">...</option>
</select>

It should only be necessary if multiple options can be selected however.

Also, there seems to be a typo:

<?php if($tranquantity==$tranquantity)

That check will always return true. It should probably be:

<?php if($tranquantity==$gettranquantity)

Answer 2

hi all i just got the code on how to fecth the value to dropdown. actually i made a wrong word. pre-selected is the right one, sorry for that. here;s the working code.

 <select name="selectmedicine" class="form-control col-sm-4" id="medicinename">
        <option id="0" style="width:100px"></option>
        <?php

        $medicine = mysql_query("SELECT * FROM medicine");
        while ($row = mysql_fetch_array($medicine)) {
        echo '<option id="' . $row['medicinename']  . '"';
        echo ' value="' . $row['medicineid'] . '"';
        if($row['medicinename'] == $trandescription) {
        echo ' selected="selected"'; 
        }
        echo '>';
        echo $row['medicinename'];
        echo '</option>';               

  }

        ?>
        </select>

thanks everyone, whos trying to help me on this. actually this is my five revised question sorry for that. and finally i got the right one.