Show DateTime value as boolean in SalesLogix DateGrid

One time I received a request to add a new column to a dategrid. The client wanted to show a datetime field in the grid to indicate if a thing has been completed or not. However there are already too many dates in the current grid and the client only cares about if the field has a value or not, instead of the real value itself. I added the field but set the date type to be boolean, then in "Format" field put the desired wording when the value is not NULL. It will show blank when the datetime value is NULL. It perfectly solved the problem.