Optional Prompt Not Working

Dear Experts ,

In my report I am using Following Command ,

Select  field name  from table name where

   Company_code='{?Company_Code}' and     branch_code='{?Branch_Code}' and    location_code='{?Location_Code}' and    job_no='{?Job_No}' and

    segment_code='{?Segment_Code}'

and also in Select Expert -> Record -> if HASVALUE ({?Vehicle_No}) then {CR_21061.VEHICLE_NO} in {?Vehicle_No}

In Value Option Screen , Vehicle_no parameter I am selected Optional Prompt Value = TRUE .

In my job I have 2 vehicles ,if Vehicle Parameter is empty , I want to retrieve all vehicle for that particular job ,

Now I am getting Empty report if vehicle parameter is Empty , Please check my image file .