Load the teaching dataset

Choose Transform data → New source → Blank query. Open Advanced Editor, replace its contents with the M below and name the query OrderLines. Choose Close & Apply. The query creates eight lines and derives the late flag and remaining value.

let
    // Fixed teaching snapshot, not today's live position.
    AsOf = #date(2026, 10, 15),
    Source = #table(
        type table [OrderNo = text, LineNo = number,
            Supplier = text, Site = text, DueDate = date,
            Status = text, RemainingQty = number,
            UnitPriceGBP = number, Buyer = text],
        {
            {"PO1001",1,"A100 | Arden Components","North",#date(2026,10,9),"Open",20,120,"Alex"},
            {"PO1001",2,"A100 | Arden Components","North",#date(2026,10,12),"Open",10,180,"Alex"},
            {"PO1002",1,"A100 | Arden Components","South",#date(2026,10,14),"Open",50,100,"Alex"},
            {"PO1003",1,"B200 | Beacon Supplies","North",#date(2026,10,8),"Open",30,200,"Sam"},
            {"PO1004",1,"C300 | Cedar Industrial","South",#date(2026,10,13),"Open",20,150,"Jo"},
            {"PO1005",1,"B200 | Beacon Supplies","North",#date(2026,10,15),"Open",10,70,"Sam"},
            {"PO1006",1,"C300 | Cedar Industrial","South",#date(2026,10,5),"Closed",0,100,"Jo"},
            {"PO1007",1,"A100 | Arden Components","North",#date(2026,10,2),"Cancelled",10,50,"Alex"}
        }
    ),
    Typed = Table.TransformColumnTypes(Source,
        {{"LineNo", Int64.Type}, {"UnitPriceGBP", Currency.Type}}),
    WithKey = Table.AddColumn(Typed, "OrderLineKey",
        each [OrderNo] & "-" & Text.From([LineNo]), type text),
    WithValue = Table.AddColumn(WithKey, "RemainingValueGBP",
        each [RemainingQty] * [UnitPriceGBP], Currency.Type),
    WithLate = Table.AddColumn(WithValue, "IsLate",
        each if [DueDate] = null then false else
            [Status] = "Open" and [RemainingQty] > 0
            and [DueDate] < AsOf, type logical),
    WithDays = Table.AddColumn(WithLate, "DaysLate",
        each if [IsLate] then Duration.Days(AsOf - [DueDate])
            else 0, Int64.Type),
    WithSnapshot = Table.AddColumn(WithDays, "SnapshotDate",
        each AsOf, type date)
in
    WithSnapshot

The snapshot is deliberately fixed at 15 October 2026. In production, replace it with an authoritative business snapshot date delivered alongside the order extract. A new calendar day does not make an imported dataset current. Display the snapshot date prominently and agree the UK reporting cut-off.

Quarantine missing due dates for correction rather than treating them as healthy orders. The sample excludes them from the late flag; monitor their count separately. Validate duplicate line keys, negative quantities and unrecognised statuses before adopting the calculation.

Create the measures

Under New measure, create each definition separately. Format Late Remaining Value GBP as pounds sterling with zero or two decimal places; keep the count measures as whole numbers.

// Create each definition separately using New measure.
Late Lines =
COALESCE(
    CALCULATE(COUNTROWS(OrderLines),
        KEEPFILTERS(OrderLines[IsLate] = TRUE())), 0)

Late Orders =
COALESCE(
    CALCULATE(DISTINCTCOUNT(OrderLines[OrderNo]),
        KEEPFILTERS(OrderLines[IsLate] = TRUE())), 0)

Late Remaining Value GBP =
COALESCE(
    CALCULATE(SUM(OrderLines[RemainingValueGBP]),
        KEEPFILTERS(OrderLines[IsLate] = TRUE())), 0)

Detail Heading =
"Late orders | " &
SELECTEDVALUE(OrderLines[Supplier], "Select one supplier")

KEEPFILTERS intersects the late condition with the current context. Do not remove supplier or site filters to force a grand total into the detail page. The distinct order count assumes OrderNo is unique across the reporting scope; otherwise use a company-plus-order key.

Build the supplier overview

Create a page named Supplier overview. Add cards for the three numeric measures, a bar chart with OrderLines[Supplier] on its category axis and Late Remaining Value GBP as its value, and a slicer using OrderLines[Site]. Sort the chart by value descending.

With no site selection, expect 5 late lines, 4 late orders and £18,200 — Illustrative example. Use the combined supplier code and name supplied in the sample, rather than assuming supplier names are unique.

Create the detail destination

Add a page named Late order detail. Select its canvas and find the Drillthrough field well in the report-building pane. Add the exact OrderLines[Supplier] column used by the chart. Retain the automatically created Back button.

Add OrderLines[IsLate] to Filters on this page and select True. Add a table containing OrderLineKey, OrderNo, LineNo, Supplier, Site, DueDate, RemainingQty, RemainingValueGBP, DaysLate and Buyer. Set the raw numeric columns to Don't summarise where applicable and sort DaysLate descending.

Add a card using Detail Heading, plus cards for late lines and late value. Display SnapshotDate as a date, not its automatic hierarchy. The explicit page filter is essential: filtering inside a measure does not automatically restrict the rows of another visual.

Make navigation discoverable

Right-click the Arden supplier bar and choose Drillthrough → Late order detail. Confirm the supplier heading and use Back to return. Then add a source-page button labelled View late order lines, enable its Action, choose Drillthrough and set the destination.

Place an instruction beside it: “Select one supplier, then view late order lines.” In Desktop editing mode, hold Ctrl while clicking to test the button. Test the enabled and disabled states. A plain page-navigation action is not a substitute for passing drillthrough context. Keep the right-click route available while testing button behaviour.

Prove the filter contract

Compare the report with this acceptance table. All figures are an Illustrative example calculated from the supplied dataset. Clear the destination's temporary design filters before the final test.

For the empty-state test, use the Site slicer and a temporary Supplier slicer to select North and Cedar together: there are no matching sample lines. Cards should show zero and the table should be empty; no unrelated supplier should appear. Verify this state using slicers rather than expecting a zero-value bar to provide a drillthrough target.