query problem in php

[tom s]

Hi, i'm trying to select data from different tables, i've done it before without problems but for some reason this doesn't work. I've already lost several hours on this one.

$result = mysql_query("select * FROM ordercheck, orderdetails, items WHERE ordercheck.ordernr='$ordernr' AND orderdetails.label2=items.label AND orderdetails.cookieId=ordercheck.cartId");


problem seems to be in the:
orderdetails.label2=items.label
part

Both those fields exist but i keep getting this error:
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource

if i change the fields or leave them out there's no error. Both fields are "text" type.

it's driving me insane, all help much appreciated

thanks