Referring to previous <SELECT> in a new <SELECT>

[fouwaaz]

Hello PHP Gurus,

Thanks very much for the responses to my earlier query regarding drop-down lists.

Now I have created a list of values for the end-user querying records from a table in MySQL. The problem is that I want the user to select from a second list that derives from the first. e.g. first list was categories returning category_id ($x). Second list will select sub-categories where category_id = $x.

Is this possible?

With Best Regards

[rIkLuNd]

Depending on your form method, you have to do something like this:

<?php

$query = "SELECT * FROM table WHERE cat='".$_POST['cat']."'";
mysql_query($query);

?>

OR

<?php

$query = "SELECT * FROM table WHERE cat='".$_GET['cat']."'";
mysql_query($query);

?>

[martinperez]

If I understood right you need JavaScript to achieve this.

Please visit the following example and tell me if that's what you need.

http://www.reduruguay.com.uy/test2.php

The code I have to generate this page is for php/postgres, but you can easily convert it to any sql !!!

[fouwaaz]

The example at http://www.reduruguay.com.uy/test2.php appears to be exactly what I want!

A snippet of my code for the first category segment is as follows:

$query="select * from merchandise_major_categories";
$result=mysql_query($query);
echo "<select name='category'>";
while($row = mysql_fetch_array($result)){
echo "<option value=\"".$row['merchandise_major_cat_id']."\">".$row['merchandise_major_cat_name']."</option>"."\n";
}
echo "</select>";
echo "</br>";

Now I need to query another table for rows having merchandise_major_cat_id = <to the one selected>.

Thanks & Regards

[martinperez]

Try the following code:
Remember to use your tables and columns names.!!!

<FORM action="" METHOD="POST" NAME="yourformname">
<select name="category" onchange="CambiaDropDowna(this.form)"> 
[code=php]
<?
$query="SELECT * FROM merchandise_major_categories"; 
$result=mysql_query($query); 
	while($row = mysql_fetch_array($result)){ 
		echo "<option value=\"".$row['merchandise_major_cat_id']."\">".$row['merchandise_major_cat_name']."</option>"."\n"; 

	//Now we query another table for rows 
	//having merchandise_major_cat_id. 
	$queryb="SELECT * FROM merchandise_minor_categories WHERE merchandise_major_cat_id = $row['merchandise_major_cat_id']"; 
	$resultb=mysql_query($queryb); 

	$droplist .= "dropd".$row['merchandise_major_cat_id']."\=\'";
	while($rowb = mysql_fetch_array($resultb)){ 
		$droplist .= "<option value=\"".$rowb['merchandise_minor_cat_id']."\">".$rowb['merchandise_minor_cat_name']."</option>".""; 
	}
	$droplist ="';\n";


} 
echo "</select></br>"; 
?>

<div id="subcatSela">
<select name="subcategory">
<option value="">Select subcategory --></option>
</select>
</div>

<script language="javascript1.2">
NS = (!document.layers) && (navigator.userAgent.indexOf('Netscape')!=-1)?true:false;
IE = (document.all)? true:false

<?= $droplist ?>

function CambiaDropDowna(marcador) {
marcador = marcador.category.options[marcador.category.selectedIndex].value;
var dmcontent = eval("dropd" + marcador);
if (dmcontent) {
temp = '<select name="subcategory">"<option value=""></option>"' + dmcontent + '</select>';
}else{
temp = '<input type=text name=new_subcategory>Sugest a subcategory';
}
if(IE) {
subcatSela.innerHTML=(temp)
}else if (NS){
document.getElementById('subcatSela').innerHTML = (temp);
}

}

</script>
<noscript></noscript>

</form>
[/code]

Good luck!!!