Get next line from Related Table (Table.)

Hi EvertonRosa 

I don't see your original code working...based on my understanding, you have a table like the screenshot, another table called dCalendarA. While you fetch the dCalendarA.CloseDate, you are looking at Month/Year in both tables to match? I modified your code a little bit, let me know if you want something else

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjy0QElH6dACI0t9A0N9IwMjQyDXwBDEAMs4lpQm5ijF6oyqHLwqA4ryKzJz80lWawRTa6ZvYARXa4TFBdRTSYr9cLWxAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [id = _t, DataFechamento = _t, #"Month/Year" = _t, FiscalPeriod = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"id", Int64.Type}, {"DataFechamento", type date}, {"Month/Year", Int64.Type}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each 
let data = Table.Column(dCalendarA, "Month/Year") in
if [FiscalPeriod] = null then null
else if [FiscalPeriod] = "Atual" then dCalendarA[CloseDate]{List.PositionOf(data, [#"Month/Year"])}
else try dCalendarA[CloseDate]{List.PositionOf(data, [#"Month/Year"])+1} otherwise null)
in
    #"Added Custom"