How to check null value for number column in webgen2 report filter

Summary:

How to check null value for number column in webgen2 report filter

Content (please ensure you mask any confidential information):

I am trying to create a report where we wanted to list down orders where we didnn't get line details from EBS got only header details. To do that I am trying to add filter on order_hdr.TOTAL_ORIG_ORD_QTY to check if that value is null. As we don't get any value in that column in case if we don't get line dtails. How to add null condition on that column as its number. I tried using IsNull(order_hdr.TOTAL_ORIG_ORD_QTY) = 'True'. If Add that condition and try to run report it not even completing its run. Its getting hanged