How to filter a column based on a column from another table?

[rahme]

I have Table 1 that contains a column of ALL of my employees:

Employee ID	Sales Value
1	25
2	50
3	75
4	100
5	100

I have Table 2 that contains a SUBSET of employees and their info:

Employee ID	First Name	Last Name
2	Jon	Doe
4	Jane	Doe

I want to filter my Table 1, so that it only contains rows that show up in Table 2. Table 1 after the filter should look like this:

Employee ID	Sales Value
2	50
4	100

How do I achieve this? Bonus: is there a way to achieve this without doing a Join? The tables are millions of rows long, so I don't know how join would impact performance.

[Icey]

Hi @rahme ,

You can also try this:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTIyVYrViVYyAjJNDcBMYyDTHCJqAmQaGkCETWHsWAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Employee ID" = _t, #"Sales Value" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Employee ID", Int64.Type}, {"Sales Value", Int64.Type}}),
    #"Filtered Table1" = Table.SelectRows(#"Changed Type", each List.Contains(#"Table2"[Employee ID],[Employee ID]))
in
    #"Filtered Table1"

Best Regards,

Icey

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[AlB · Accepted solution]

Hi @rahme 

An inner join should do it and is quite probably the best performing option 

Place the following M code in a blank query to see the steps.

let
    Source = Table.NestedJoin(Table1, {"Employee ID"}, Table2, {"Employee ID"}, "Table2", JoinKind.Inner),
    #"Removed Columns" = Table.RemoveColumns(Source,{"Table2"})
in
    #"Removed Columns"

Please accept the solution when done and consider giving a thumbs up if posts are helpful.  Contact me privately for support with any larger-scale BI needs, tutoring, etc.