How to compare the rows in the same table and create a separate column in power query or DAX?

It wasn't clear what is the output expected. Are you looking for each ID latest date or a way to identify the latest record?

I provided both DAX and power query ways and tweak to your needs!

Say, if you want only latest records, filter "Latest ID Record" as 1.

Power Query

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jdBLDoAgDEXRvTA2Ka/Qgmsx7H8b8ouKmsCggcHJTeE4DITZm80IORBbhHy3edDPNmm75U6sRepD4C1luVmlkj7hT9J7yFqyy0iIRcogRqmWS4OJazS+GD506UXaJMKkecmx+fefzuriop1OFk0n", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ID = _t, Date = _t, En = _t, Gd = _t, Wd = _t, Gd1 = _t, Wd1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"ID", Int64.Type}, {"Date", type date}, {"En", Int64.Type}, {"Gd", Int64.Type}, {"Wd", Int64.Type}, {"Gd1", Int64.Type}, {"Wd1", Int64.Type}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"ID"}, {{"Latest Date by ID", each List.Max([Date]), type nullable date}, {"allRows", each _, type table [ID=nullable number, Date=nullable date, En=nullable number, Gd=nullable number, Wd=nullable number, Gd1=nullable number, Wd1=nullable number]}}),
    #"Expanded allRows" = Table.ExpandTableColumn(#"Grouped Rows", "allRows", {"Date", "En", "Gd", "Wd", "Gd1", "Wd1"}, {"Date", "En", "Gd", "Wd", "Gd1", "Wd1"}),
    #"Added Custom" = Table.AddColumn(#"Expanded allRows", "Latest ID Record", each if ( [Latest Date by ID] = [Date]) then 1 else 0, Int64.Type),
    #"Reordered Columns" = Table.ReorderColumns(#"Added Custom",{"ID", "Date", "En", "Gd", "Wd", "Gd1", "Wd1", "Latest Date by ID", "Latest ID Record"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Reordered Columns",{{"ID", Int64.Type}, {"Date", type date}, {"En", Int64.Type}, {"Gd", Int64.Type}, {"Wd", Int64.Type}, {"Gd1", Int64.Type}, {"Wd1", Int64.Type}, {"Latest Date by ID", type date}, {"Latest ID Record", Int64.Type}})
in
    #"Changed Type1"

Output:

DAX 

Say, your data looks as below:

Measures:

Latest Date by ID = CALCULATE( Max( TableRank_Dups[Date]), FILTER(ALLSELECTED(TableRank_Dups), TableRank_Dups[ID] = max(TableRank_Dups[ID])))


Latest ID Record = 
IF ( HASONEVALUE( TableRank_Dups[ID]) && HASONEVALUE(TableRank_Dups[Date]) ,
 IF (Max( TableRank_Dups[Date]) = [Latest Date by ID] , 1, 0)
 , blank())

/*
IF ( HASONEVALUE( TableRank_Dups[ID]) && HASONEVALUE(TableRank_Dups[Date]) ,
 IF (Max( TableRank_Dups[Date]) = CALCULATE( Max( TableRank_Dups[Date]), FILTER(ALLSELECTED(TableRank_Dups), TableRank_Dups[ID] = max(TableRank_Dups[ID]))), 1, 0)
 , blank())
 */

Output:

I think you can use either DAX or Power Query way like I provided.

In the table visualization, filter those only with "Latest ID Record" as 1.

Or you want to use in a measure, you can do this as :

Measure = 

var _t = Filter( ALLSELECTED(TableRank_Dups), [Latest ID Record] = 1)

RETURN CALCULATE( Sum(TableRank_Dups[En]) + Sum(TableRank_Dups[Gd]) + Sum(TableRank_Dups[Wd]) + sum(TableRank_Dups[Gd1]) + sum(TableRank_Dups[Wd1]) , _t)

Say, if you want individual measures, You can modify this measure logic for your needs. 

Tips:

It is a common scenario.

Say, if you have many rows, I will rather create in Power Query than doing in DAX.

Say, if you want ease of use or some large number of rows, I will create another table in Power Query as latest records table and filter only those with latest records.

Thanks