Variable does not work in query

[Givike]

I'm building a navigation system that calls up links according to its category.

I have the following code:

<?php

$categorizering = mysql_query('SELECT tblcategorie.categorienaam, tblcategorie.categorieid FROM tblcategorie') or die(mysql_error());


while ($fetchcategorie = mysql_fetch_array($categorizering))
	{	
	$categorienaam = $fetchcategorie['categorienaam'];
	$categorieid = $fetchcategorie['categorieid'];

	echo "<p><b>$categorienaam, $categorieid</b></p>";

	$navigatie = mysql_query('SELECT tblrecept.receptid, tblrecept.receptnaam  FROM tblrecept WHERE (tblrecept.categorieid = "$categorieid")') or die(mysql_error());	

		while ($fetchlinks = mysql_fetch_array($navigatie))
		{
			$receptID = $fetchlinks['receptid'];
			$receptnaam = $fetchlinks['receptnaam'];

			echo "<a href='recept.php?id=$receptID'>$receptnaam</a><br />";
		}
}
?>

The problem is that I can call up the variable....

$categorieid = $fetchcategorie['categorieid'];

and it works but when I use this variable and put it down here...

$navigatie = mysql_query('SELECT tblrecept.receptid, tblrecept.receptnaam  FROM tblrecept WHERE (tblrecept.categorieid = "$categorieid")') or die(mysql_error());	

it doesn't work.

When I replace "$categorieid" with "1", then it does work.

Don't come with your way of writing a query. The problem is that no number is passed on. Not that the query is written wrongly because as I said, if replaced by a number, it works perfectly fine.

[SOLVED] TY Laserlight

[laserlight]

The problem is that in single quoted strings, PHP variables are not interpreted as such. You should either concatenate (join) them, or use double quoted strings. Also, SQL strings are single quoted, not double quoted. As such, you should write:

$navigatie = mysql_query("SELECT tblrecept.receptid, tblrecept.receptnaam  FROM tblrecept WHERE tblrecept.categorieid = '$categorieid'") or die(mysql_error());

Don't come with your way of writing a query.

Actually, you are executing queries in a loop, which is typically a Bad Thing. So, a likely better solution is to use a join.

EDIT:
Here is a possible untested solution using a join:

<?php

$query = "SELECT C.categorienaam, C.categorieid, R.receptid, R.receptnaam
    FROM tblrecept R, tblcategorie C
    WHERE R.categorieid=C.categorieid
    ORDER BY C.categorieid";
$result = mysql_query($query) or die(mysql_error());

$categorieid = 0;
while ($row = mysql_fetch_assoc($result))
{
    if ($row['C.categorieid'] != $categorieid)
    {
        $categorieid = (int)$row['C.categorieid'];
        $categorienaam = htmlspecialchars($row['C.categorienaam']);
        echo "<p><b>$categorienaam, $categorieid</b></p>";
    }

$receptID = (int)$row['R.receptid'];
$receptnaam = htmlspecialchars($row['R.receptnaam']);
echo "<a href='recept.php?id=$receptID'>$receptnaam</a><br />";
}

?>

Only one SQL statement is executed, which is much more efficient.