Adding the item Is Null to the relations-listbox in the Advanced Query Form should help (I think). The problem is when you put "Is Null" in the Fieldvalue field you get the '=' in the sql-statement: (a0108a0324a0318a0322.RenditionNumber = Is Null))) this should be RenditionNumber Is Null I think the data in the listbox is hardcoded in tms because the table dbo_QueryDetails refers to the 7 choices in the listbox only with the numbers 0 through 6 in the Operator field. I will be very happy if Gallery Systems solves the problem in the next upgrade, I think for them it is rather easy to fix. André Straatman Registrar Kröller-Müller Museum, Otterlo, The Netherlands tel. +31-(0318)-596 168, fax +31-(0318)-592 209