Question

I have a drop down menu and I would like to use the selection in a query.

Say I have the following, this is actually loaded from a db on my site but to limit the amount of code I post:

<select id="parent" name="parent">
<option value="P1">parent 1</option>
<option value="P2">parent 2</option>
</select>

I want to query the child table for P1 or P2 depending on what was selected so I have the following query:

$selected_parent=$_REQUEST['parent'];<-- Not sure if this is right at all

$query = "SELECT parent.*, child.* 
          FROM parent 
          INNER JOIN child 
          ON parent.value = child.parent
          WHEN parent.value = '$selected_parent'";

I would have the two following tables:

PARENT                 CHILD
ID   NAME     VALUE    ID    NAME    PARENT
01---parent1--P1       01----child1--P1
02---parent2--P2       02----child2--P1
03---parent3--P2       03----child3--P2

I know this is open to SQL Injection, I will fix it later, more curious as to how the variable working within a query

EDIT: Currently I get no results when using ‘$selected_parent.’

Thanks in advance

Answer 1

You’re extremely close, the only change I can see would be to wrap the dropdown box in a form tag, such as:

<form action="<?php echo $_SERVER['php_self']; ?>" method="POST">
    <select id="parent" name="parent">
        <option value="P1">parent 1</option>
        <option value="P2">parent 2</option>
    </select>
</form>

And then when you’re getting the variable, use $_POST instead of $_REQUEST:

$selected_parent=$_POST['parent'];

Other than that your query should work just fine.