Linear expression from a specific date

[brunolelli87]

Hello guys!

First of all, I would like to thanks everybody here who is helping me a lot. I'm learning too much here, and I believe I'm working with QlikView 12 horas a day, for more than a month. This software is amazing!

Now my question is:
How can I calculate (via expression), the linear trendline, starting from a specific date ('18/03/2020')?

Look at that:

In this case, QlikView is calculating the overall Trendline (based on my dates selection), but I would like to get something like this - see below:

I'm currently working with the following expression, but I'm not getting the correct result:

if( DVPG > '18/03/2020',
	linest_m(total aggr(if(sum(VDAF) ,sum(VDAF)), DVPG), DVPG)
	* only(DVPG) + linest_b(total aggr(if(sum(VDAF) ,sum(VDAF)), DVPG), DVPG)
)

This is the chart I'm getting, and obviouly it's correct:

The Date field is called DVPG, and the Y axis field is called VDAF.

How can I do that?
Thanks

[brunolelli87]

Hey guys, I think I got it with the following expression:

=If(DVPG > '18/03/2020',
(LINEST_M(TOTAL Aggr(avg(DISTINCT If(DVPG > '18/03/2020', VDAF)), DVPG), DVPG) * DVPG)
+LINEST_B(TOTAL Aggr(avg(DISTINCT If(DVPG > '18/03/2020', VDAF)), DVPG), DVPG))

What do you guys think about this solution?

Thanks