Implementing Common Calculations In Power Query – Chris Webb's BI Blog
let Source = Excel.CurrentWorkbook(){[Name="Table4"]}[Content], Subtotals = Table.Group(Source, {"Category"}, {{"Category Sales", each List.Sum([Sales]), type number}}), JoinTables = Table.Join(Source, "Category", Subtotals, "Category"), InsertedCustom = Table.AddColumn(JoinTables, "Share", each [Sales]/[Category Sales]), RemovedColumns = Table.RemoveColumns(InsertedCustom,{"Category Sales"})in RemovedColumns