How can I use "?" instead of if statement?

if (entity.ScdDept == "") 
  command.Parameters.AddWithValue("@SCD_DEPT", DBNull.Value);
else 
  command.Parameters.AddWithValue("@SCD_DEPT", entity.ScdDept);

if (entity.LeaveDate == DateTime.MaxValue) 
   command.Parameters.AddWithValue("@LEAVE_DATE", DBNull.Value);
else  
   command.Parameters.AddWithValue("@LEAVE_DATE", entity.LeaveDate);

It works like that. But I want to use ? instead of if

I tried like that:

var result = entity.scdDept = " " ? command.Parameters.AddWithValue("@SCD_DEPT", DBNull.Value :  entity.ScdDept;

This doesn't works but I need like that one line solving. Thank you for all your helps.