SYNTHETIC EXCEL POWER QUERY PRACTICE

Not executed in Excel or Power Query. M functions checked against Microsoft
documentation on 2026-10-16. Expected output independently calculated.

Create THREE separate blank queries with the exact names below. Paste only the
let...in expression for each into its Advanced Editor. Change the literal file
paths to your dedicated synthetic practice folder. Keep privacy checks enabled.
Do not use confidential files or apply Public classification to broader folders.

QUERY NAME: StageNorth

let
    Source = Csv.Document(
        File.Contents("C:\ExcelPractice\firewall-north.csv"),
        [Delimiter=",", Columns=3, Encoding=65001, QuoteStyle=QuoteStyle.Csv]
    ),
    Headers = Table.PromoteHeaders(Source, [PromoteAllScalars=true]),
    Typed = Table.TransformColumnTypes(
        Headers,
        {{"Record", type text}, {"Item", type text}, {"Units", Int64.Type}}
    )
in
    Typed

QUERY NAME: StageSouth

let
    Source = Csv.Document(
        File.Contents("C:\ExcelPractice\firewall-south.csv"),
        [Delimiter=",", Columns=3, Encoding=65001, QuoteStyle=QuoteStyle.Csv]
    ),
    Headers = Table.PromoteHeaders(Source, [PromoteAllScalars=true]),
    Typed = Table.TransformColumnTypes(
        Headers,
        {{"Record", type text}, {"Item", type text}, {"Units", Int64.Type}}
    )
in
    Typed

QUERY NAME: CombinedPractice

let
    Combined = Table.Combine({StageNorth, StageSouth})
in
    Combined

StageNorth and StageSouth can be connection-only. Load CombinedPractice to a
worksheet. Expected: four records N-01, N-02, S-01, S-02; Units 3, 2, 4, 5;
total 14. Changing only S-02 to 6 in the synthetic South CSV and refreshing
should produce total 15 with four records. Restore it to 5 after practice.

Staging is not a guarantee of successful refresh for arbitrary connectors or
privacy boundaries. The practice does not deliberately force a Firewall error.