Query Field To Concatenate Fields With Nil Values

I have an Access 2000 project and am trying in a query view to join 3 values into one.
2 of the values come from tables, the third comes from another query view (all linked in the query design screen)

Value 1 is always populated, but for each record either Value 2 or Value 3 will always be empty.
All values are strings.

I have tried this formula in the query design grid:

dbo.Value1 + '/' + dbo.Table2.Value2 + dbo.vieTable3.Value3


..in an attempt to give the result Value1/Value2 or value1/Value3 according to the
particular record.

Unfortunately it doesn't work! ...just returns blank results when the query view is run.


Any suggestions would be greatly appreciated

thanks....nick