DateSpan

Hi nchamilton2 ,

You're correct that directly joining the DateSpan table to the FactTable introduces a many-to-many relationship, which Power BI doesn’t handle as cleanly as other analytics tools. To support your scenario generating all dates between each phase’s estimated start and end, while avoiding many-to-many joins the recommended approach is to reshape the model slightly by introducing Phases as a bridge table.

First create a dynamic DateSpan table in Power Query that expands each phase into one row per date using this code:

let
    Source = Phases,
    ChangedTypes = Table.TransformColumns(Source, {
        {"EstStartDate", each Date.FromText(_, "en-US"), type date},
        {"EstEndDate", each Date.FromText(_, "en-US"), type date}
    }),
    AddDateList = Table.AddColumn(ChangedTypes, "Date", each List.Dates([EstStartDate], Duration.Days([EstEndDate] - [EstStartDate]) + 1, #duration(1,0,0,0))),
    ExpandedDates = Table.ExpandListColumn(AddDateList, "Date"),
    SelectedColumns = Table.SelectColumns(ExpandedDates, {"PhaseId", "Date", "PhaseName"})
in
    SelectedColumns

Adjust the relationships in the model:

• DynamicDateSpan[PhaseId] → Phases[PhaseId] (One-to-many)
• FactTable[PhaseId] → Phases[PhaseId] (Many-to-one)
• FactTable[ProjectID] → Projects[ProjectID] (Many-to-one)

Use Phases as the central bridge. This lets both the fact table and the generated date list connect indirectly, avoiding many-to-many conflicts.

To show ProjectTitle, you can either create a measure like:

ProjectTitle :=
CALCULATE (
    SELECTEDVALUE ( Projects[ProjectTitle] ),
    TREATAS ( VALUES ( DynamicDateSpan[PhaseId] ), FactTable[PhaseId] ),
    FactTable
)

Or build a calculated table if you need a flattened structure.

This setup should meet your needs: dynamically showing each phase across all active dates, with project info, while maintaining a clean and performant model.

hope this helps, please feel free to reach out for further issue.

Thank you.