Thanks for the reply. Sorry, I'm a newbie and I didn't quite understand the parameter part. I understood the Calculation part though. And one more thing I would like to add is that I need both the trend lines in one graph itself. If you could please elaborate parameter part, would be really helpful.
Parameter is like filter only but we can access single value in parameter or all values.
in my calc part i have added parameter as [select].
If [select] <[Order Date] THEN "Before" ELSE "After" END
if our selected date less then order date then it will show before else after.
Attached workbook will help.
trend line.twbx 1.2 MB