Dynamic Conditions in PHP form

I have this:
SELECT $items FROM $table WHERE $conditions

in my form I'm asking the user to select items from a list - multible selections
and I'm asking the user to select from which table he/she would like to extract the data

now my problem with the conditions selection !

I'm going to divide this problem to smaller ones and solve each one then relate it to the other

I've already created a list that have all the fields available (user can only select one item)
and I've already created a list with the values (multible selection is available)

example:
item1 is being chose___user can choose the relation(In/Not In..etc)___list of unique values of item1

should i use java to remember the first selection then i can use this selection in my second list sql so i can get the values that are related to this selection ?

do you know any java script that will save selection then read it later and use it as a variable in my second sql ?

 

There's something I don't understand here !

in order in use $_POST, you need to submit the form, right ?

look at this:

Code:

<?
$firstQry = mysql_query("SHOW FIELDS FROM table1") or die(mysql_error());      // table 1
?>
<form name="check" method="post">
        <select name="first" onchange="this.form.submit()">
            <?
                while($res = mysql_fetch_row($firstQry))
                {?>
                   <option  value="<? echo $res[0]?>"><? echo $res[0]?></option>
             <? }
                unset($firstQry,$res);?>
        </select>

        <? if(isset($_POST["first"]))
        {
        $sql2 = "Select ".$_POST['first']." FROM table1 GROUP BY ".$_POST['first'];
        $secondQry = mysql_query($sql2) or die(mysql_error());
?>        <select size="3" multiple name="second[]">
            <? while($row = mysql_fetch_row($secondQry)){?>
                <option  value="<? echo $row[0]?>"><? echo $row[0]?></option>
            <? }
           } unset($secondQry,$row);?>
        </select>
</form>

<?
echo "<br/>";
echo "first: ".$_POST['first'];

echo "<br/>";
echo "second: ".implode($_POST['second'],",");

the problem is

when i choose item2 in the first list
values of item2 appear in the second list

then
when i select few values from second list
and select a new field in first list ( let's say item5 )

form is submitted ! I get as an output
list1 = item 5
list2 = values of item2

what i need is the match to appear.. item 2 with its values

 

You'll have to select the multiple items first and the the select box above!

 

oh sorry didn't get what did you mean !

can you please explain more

 

okay let me forget for now doing the dependent lists

first this is what i'm planning to have

http://img76.imageshack.us/my.php?image=criteriafz2.jpg

I'm wondering how can i by a click have a new criteria line

then all criteria lines should be saved to thier variables ! so i can use them later inside a sql query statement after the word "WHERE"

do i have to use java script ! .. or do i have to use php functions ! or multiple forms submitions !! ..