Help with custom column

Hi craig811 ,

We can create a custom column and expand it to meet your requirement:

let c = [Entered Currency]
in Table.SelectRows(Exchange_Rates,each [Currency] = 
c)

All the queries are here:

Exchange_Rates:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUbJUitWJVnICsgwNwExnENMQzHQBMs3BLFcgy1gpNhYA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Currency = _t, #"Exchange Rate" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Currency", type text}, {"Exchange Rate", Int64.Type}})
in
    #"Changed Type"

Combined_for_GL_Check:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclSK1YlWcgKTzmDSBUy6KsXGAgA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [#"Entered Currency" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Entered Currency", type text}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Rate", each let c = [Entered Currency]
in Table.SelectRows(Exchange_Rates,each [Currency] = 
c)),
    #"Expanded Rate" = Table.ExpandTableColumn(#"Added Custom", "Rate", {"Exchange Rate"}, {"Rate.Exchange Rate"})
in
    #"Expanded Rate"

Or we can create a calculated column to meet your requirement:

Rate_Dax = LOOKUPVALUE('Exchange_Rates'[Exchange Rate],'Exchange_Rates'[Currency],[Entered Currency])

 
Best regards,