Increase from the previous month

hi lionelv,

Try this:

let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hZIxCsMwDEWvYjynQrLkOL5Bp14gZOjgoUMpNC29Ts/SkzUlGlyIHGwwhvck9O1x9MfL/Lj5zgekeEBa9nIhQMzL6T7v/+U4JJDe+anbUIOqbKgDiBgqqxoMNQOhoYqqcVtlhBQNNa4qGV1ZIAVD7bVrMtQEqDGdystdy3l+3ktdIGmBX94tbqiSaXG5iqHBEerMvMPpPyDZ4fTRaZ1j+gI=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Source = _t, Month = _t, Increase = _t, Amount = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Source", type text}, {"Month", type date}, {"Increase", type number}, {"Amount", type number}}),
#"Added Index_0..n" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
#"Added Index1_1...n" = Table.AddIndexColumn(#"Added Index_0..n", "Index.1", 1, 1, Int64.Type),
#"Merged Queries" = Table.NestedJoin(#"Added Index1_1...n", {"Index"}, #"Added Index1_1...n", {"Index.1"}, "Added Index1", JoinKind.LeftOuter),
#"Expanded table to get previous month amount" = Table.ExpandTableColumn(#"Merged Queries", "Added Index1", {"Amount"}, {"Added Index1.Amount"}),
#"Final Amount( prev month $ * increase)" = Table.AddColumn(#"Expanded table to get previous month amount", "Final Amount( prev month $ * increase)", each [Added Index1.Amount]*[Increase]),
#"Changed Type1" = Table.TransformColumnTypes(#"Final Amount( prev month $ * increase)",{{"Final Amount( prev month $ * increase)", type number}})
in
#"Changed Type1"Appreciate a thumbs up if this was helpful.

_____________

steps taken.

1. create an index column from 0 (col1).

2. create an index column from 1 (col2).

3. left join/ self merge table on index column (col1 on col2).

4. expand the table for previous month's amount.

5. create custom column to calculate previous month's amount * increase for current month.

Please accept this as a solution if the question is solved.