Omit values based on date within another table

Hi Anonymous ,

I created a sample pbix file(see the attachment), please check if that is what you want.

Method1: Handle it in Power Query Editor:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtE3NtA3MjAyVtJRMjQAEqZKsTrRSqb65jBRC5CMkVJsLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [WeekCommencing = _t, SiteID = _t, StaffNo = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"WeekCommencing", type date}, {"SiteID", Int64.Type}, {"StaffNo", Int64.Type}}),
    #"FilteredTable" =Table.SelectRows( #"Changed Type" , each not List.Contains(#"Table A"[WeekCommencing], [WeekCommencing]))
in
    #"FilteredTable"

Method2: Create a calculated column and filter it out using visual-level filter

Omit = 
VAR _date =
    CALCULATE (
        MAX ( 'Table A'[WeekCommencing] ),
        FILTER ( 'Table A', 'Table A'[WeekCommencing] = 'Table B(2)'[WeekCommencing] )
    )
RETURN
    IF ( ISBLANK ( _date ), 1, 0)

Best Regards