Drop down menu

vwgtiturbo

I am a newbie to PHP so forgive this question if it is common knowledge... Most of the reading I have done has shown me how to make basic queries and such, but I was wondering... Can you assign a php variable to a selection made by a user from an HTML drop down menu? I want to have about 6 drop down menus taht a user can either select from one menu and query a database, or select from all 6, then execute the query (to narrow the search if need be...). Thanks for any help or advice.

bubblenut

In order to pass the value from the dropdown menu to PHP you must submit the form. In these sorts of situations I tend to use javascript to submit it OnChange so the user does not have to submit after every time. Then you would pull the vars through the $GET or $POST arrays.
Could you be a little more specific with the wuery as I spent a few days playing around with an advanced search on a site a while ago and came up with a pretty nice way of dealing with it but it's only relevant if the contents of the dropdowns is dynamically populated according to what can be selected.
HTH
Bubble

vwgtiturbo

well, I have a camshaft database that has info like the manufacturer, lift numbers, etc.
what I would like to do is have a few drop down lists (i.e. one for manufacturer, one for pattern, lifter type, rocker arm ratio, duration, lobe separation angle, etc.). The thing is... each menu will have multiple choices (i.e the manufacturer one will have about 20 choices, pattern has 2, lifter type 4, ratio 2, duration will have several, etc.) I am racking my brain, especially as a newbie, as I would like the user to either select one choice from a single menu to search for a cam, or if they want to really narrow their search, use selections from all of the menus, then submit so that all menu choices will be used as search criteria.
Did I make that clear? Sometimes I am really horrible about explaining things because they are clear in my brain, but getting them out can be a pain... Thanks for the help. It is greatly appreciated 🙂

I've never dealt with javascript... this project may require that I learn more than I set out to... oh well, it only hurts in the beginning.

mrhappiness

you will have several select-boxes in html of course

<form action="search.php method="post">
<select name="manufacturer">
<option value="-1">all</option>
  <option value="manufacturer1">Manufacturer 1</option>
<option value="manufacturer2">Manufacturer 2</option>
</select>

<select name="pattern">
<option value="-1">all</option>
  <option value="pattern1">Pattern 1</option>
<option value="pattern2">Pattern 2</option>
</select>
<input type="submit" value="Search" name="search" />
</form>

in search.php you can do like this (i hope 😉) :

<?php
if (isset($_POST['search']))
//form was submitted
{
  $criteria=array();
  if ($_POST['manufacturer']!=-1)
    $criteria[]="manufacturer LIKE '%".$_POST['manufacturer']."%'";
  if ($_POST['pattern']!=-1)
    $criteria[]="pattern LIKE '%".$_POST['pattern']."%'";
  $sql='SELECT * FROM table';
  if (count($criteria)>0)
    $sql.=' WHERE '.implode(' AND ',$criteria);
  echo $sql;
}

vwgtiturbo

So, onchange... does that submit as soon as they select a choice from one of the menus? What happens to that selection? Would it just get stuffed into a variable? This is going to be fun...

mrhappiness

i wouldn't advise submitting the form every time the user changes something in one of the select-boxes

let him decide which search criterias he will need and after that let him klick the submit-button

it's much less annoying i believe 😉

bubblenut

<?php
//get the details for the query from the get vars
//or leave blank
$manufacturer_sql=($_GET['manufacturer']=="All" || !is_numeric($_GET['manufacturer']))?"":" && man_id='".$_GET['manufacturer']."' ";
$lifter_type_sql=($_GET['lifter_type']=='All' || !is_numeric($_GET['lifter_type']))?'':" && lift_id='".$_GET['lifter_type']."' ";

//build and execute query
$sql="SELECT * FROM table WHERE 1".$manufacturer_sql.$lifter_type_sql;
$res=mysql_query($sql) or die(mysql_error());
$i=0;
while($row=mysql_fetch_array($res)) {
  $results[$i]=$row;
  if(!in_array($row['man_id'],$materials) {
    $materials[]=$row['man_id'];
    $man_tmp[$m]['unique_id']=$row['man_id'];
    $man_tmp[$m]['name']=$row['man_name'];
    $m++;
  }
  if(!in_array($row['lift_id'],$lifts) {
    $lifts[]=$row['lift_id'];
    $lift_tmp[$l]['unique_id']=$row['lift_id'];
    $lift_tmp[$l]['name']=$row['lift_name'];
    $l++;
  }
  $i++;
}
//Now you have three arrays. 
//$result holds all the details
//and $mat_tmp and $lift_tmp
//hold the details for the two dropdowns
//NB To repopulate the dropdowns the user 
//must place the dropdowns back to all
//or you could have a reset search button
?>

HTH Bubble

bubblenut

i wouldn't advise submitting the form every time the user changes something in one of the select-boxes

I wouldn't agree, if you keep the page light then the reload hardly takes any time at all. The benifit being you can show the results at each stage. At the end of the day this point is down to personal preferance,
Bubble

vwgtiturbo

I knew I should have tried harder to memorize the PHP for dummies book... actually, that book turned out to be garbage. The lessons don't go in a logical order, so you have to keep skipping around. Sam's seems to be a little better...
I can't believe you can just spit that stuff out so quickly. I guess that comes with experience...
Let me just take some time to absorb all of that...
Thanks alot for the help guys. I have no programming experience at all besides html and css (which doesn't even count as programming) so the variables, and loops, if statements and such, are greek to me...

bubblenut

I got it out so quickly because I've done something very similar a little while ago, all I had to do was a quick adapdation. 😉