Working out Days since based on a flag

[Wayne74]

The logic for this one has me stumped and I am hoping the super brain collective may be able to help me.  I have been using Power BI on and off for quite a while, but still have a long way to go and a lot to learn.

Ok so I have a data source that is prestart checks for vehicles.  I have thousands of these across around 100 vehicles.  I want to be able to present the Registration number, Issue and Days since first reported for each vehicle that currently has an issue.  

Here is a dirty sample I created.  In this example I would want to show Rego 123abc, Issue 1, DATEDIFF(today, 18/03/2024).  

If it was only one vehicle I could easily sort by date (descending) and then find the first entry where Issue 1 = false.  However there are a lot of vehicles so it needs to be more dynamic.

I am sure some of you have hit similiar issues and I just need a nudge in the right direction on how to accomplish this please.

Thank you,

[Wayne74]

That will help a lot.  Thank you very much

[dufoq3]

You're welcome.

[dufoq3 · Accepted solution]

Hi @Wayne74, I'm not sure if this is what are you looking for:

Before

After

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMkxU0lEyNtA3MNY3MjAyAXJCgkJdlWJ1oFJGlrilcOsytECScnP0CUaWM8cjh9tIU6y6jJKgukwxdIGlLHDKGCPJoJuHoSkWAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [RegNo = _t, Date = _t, #"Issue 1" = _t]),
    ChangedType = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Issue 1", type logical}}),
    GroupedRows = Table.Group(ChangedType, {"RegNo"}, {{"Days since last FALSE ISSUE", each 
        [ a = List.Max(Table.SelectRows(_, (x)=> x[#"Issue 1"] = false)[Date]), //Max FALSE Date
          b = Duration.TotalDays(Date.From(DateTime.FixedLocalNow()) - a)
        ][b], Int64.Type}})
in
    GroupedRows