I've never had much luck passing a wildcard in any such fashion within a query. Is there any chance you could just put the information on a report and pass it a filter...
stDocName = "ReportName"
stLinkCriteria = "Department Like """ & IIf(IsNull([Forms]![frmTrainingHoursLess40]![cboDepartment]),"*",[Forms]![frmTrainingHoursLess40]![cboDepartment]) & """"
DoCmd.OpenReport stDocName, acPreview,,stLinkCriteria
That would be the easy way.
Alternately, you could change the SQL of the query or relevent form property. I guess this leads to 2 questions.
1 What is the sql of your query?
2 How is the query used? Maybe we can set the Rowsource of the combo box to a literal sql statement, or maybe we actually have to change an sql property.