How to query multiple choices from one table in mysql table - php

Question

I'm creating some simple search page for my little project. Its about list of Multifunctional devices and options on devices.
I have table devices and fields with device options:
option_hdd
option_fax
option_df (document feeder)
option_duplex
and so on... totally 8 option fields.
If device contain options in field is 1 if not 0.
I created small form with check boxess for all this option with GET method.
<form action="search.php" method="get" name="search">
<input name="HDD" type="checkbox" value="1" /> HDD<br />
<input name="Fax" type="checkbox" value="1" /> Fax<br />
<input name="DF" type="checkbox" value="1" /> DF<br />
...
<input name="Search" type="submit" />
</form>
I try to create some query but i don't get exact results.
If user want to check for devices which contain hdd and fax option he will check that two checkboxes and hit search, query need to return results with devices that contain checked options (not essential for other options)
i try with fallowing query's i found googling :)
SELECT * FROM devices WHERE option_hdd = '$_GET[HDD]' OR option_fax = '$_GET[Fax]' OR option_finisher = '$_GET[Df]' ......'
and also
SELECT * FROM devices WHERE option_hdd = '$_GET[HDD]' AND (option_fax = '$_GET[Fax]' OR option_finisher = '$_GET[Df]' ......);
but i do'n get wanted results... but this last is the most close-up...
Example i have 5 devices in DB for testing
All 5 devices have Hdd and 2 devices have Fax option
In form i check hdd and fax and i get result of all 5 devices, but correct results must be 2... cause only two devices have fax option...
Can somebody help me and give me correct query :)
Thanks

Answer 1

I suggest using 'AND' but...
If the checkbox is checked, the value will be 1. If the checkbox is not checked the value will be empty.
So you code will be like this:
SELECT * FROM devices WHERE option_hdd = '1' AND option_fax = ' ' AND option_finisher = '1';
Which will give you a wrong resultset.
Try this instead:
$hdd = (!empty($_GET['HDD'])) ? $_GET['HDD'] : 0;
$fax = (!empty($_GET['Fax'])) ? $_GET['HDD'] : 0;
$df = (!empty($_GET['DF'])) ? $_GET['HDD'] : 0;
$sql = "SELECT * FROM devices WHERE option_hdd = '".$hdd."' AND option_fax = '".$fax."' AND option_finisher ='".$df."'";
Another option is to build your query. Change the name of the checkboxes like in the example below:
<form action="" method="get" name="search">
<input name="option[HDD]" type="checkbox" value="1" /> HDD<br />
<input name="option[Fax]" type="checkbox" value="1" /> Fax<br />
<input name="option[DF]" type="checkbox" value="1" /> DF<br />
...
<input name="Search" type="submit" />
</form>
And see the phpexample:
$sql = 'SELECT * FROM devices';
if(isset($_GET['option']) && count($_GET['option']) > 0){
$c = 0;
$sql .= ' WHERE';
foreach ($_GET['option'] AS $key => $option) {
$sql .= ($c == 0) ? ' option_'.$key.'='.$option : ' AND option_'.$key.'='.$option;
$c++;
}
}

Answer 2

Another solution is to use this trick:
<input name="HDD" type="hidden" value="0" />
<input name="HDD" type="checkbox" value="1" /> HDD<br />
This way if PHP will revert to default 0 if it doesn't get the value from checkbox.
And please be careful with your data, don't use $_GET directly in SQL.