Look up and match values from a table containing date ranges with another date range fact table

Hi,

This M code works

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8klNVdJRckxOzi/NK0nMKwFxnJyBpFdeEZA0MNQFIiMDIwMgx9hA18AEwonViVYKz8zJoaZeX0eQ3mC4XlOYXiDLwBxDb0BiZVF+To6Cf1paZnJqEboBZnA9OkpGJroGllADYgE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Employee = _t, Position = _t, Company = _t, Lvl = _t, #"Start Date" = _t, #"End Date" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Employee", type text}, {"Position", type text}, {"Company", type text}, {"Lvl", type text}, {"Start Date", type date}, {"End Date", type date}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Date", each {Number.From([Start Date])..Number.From([End Date])}),
    #"Expanded Date" = Table.ExpandListColumn(#"Added Custom", "Date"),
    #"Changed Type1" = Table.TransformColumnTypes(#"Expanded Date",{{"Date", type date}}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type1", {"Employee", "Date"}, #"Employee salary changes", {"Employee", "Date"}, "Employee salary changes", JoinKind.LeftOuter),
    #"Expanded Employee salary changes" = Table.ExpandTableColumn(#"Merged Queries", "Employee salary changes", {"Start Date", "End Date", "Sal"}, {"Start Date_Sal", "End Date-Sal", "Sal"}),
    #"Removed Columns" = Table.RemoveColumns(#"Expanded Employee salary changes",{"Date"}),
    #"Grouped Rows" = Table.Group(#"Removed Columns", {"Employee", "Position", "Company", "Lvl", "Start Date", "End Date", "Sal"}, {{"Salary start date", each List.Min([Start Date_Sal]), type nullable date}, {"Salary end date", each List.Max([#"End Date-Sal"]), type nullable date}}),
    #"Inserted Count" = Table.AddColumn(#"Grouped Rows", "Sal start", each List.Max({[Start Date], [Salary start date]}), Int64.Type),
    #"Inserted Count1" = Table.AddColumn(#"Inserted Count", "Sal end", each List.Min({[End Date], [Salary end date]}), Int64.Type),
    #"Removed Columns1" = Table.RemoveColumns(#"Inserted Count1",{"Salary start date", "Salary end date"}),
    #"Changed Type2" = Table.TransformColumnTypes(#"Removed Columns1",{{"Sal start", type date}, {"Sal end", type date}}),
    #"Reordered Columns" = Table.ReorderColumns(#"Changed Type2",{"Employee", "Position", "Company", "Lvl", "Start Date", "End Date", "Sal start", "Sal end", "Sal"})
in
    #"Reordered Columns"

Hope this helps.