Where Clause for Custom Column

[markabdey]

Hi

In Power Query I'm trying to create a Custom Column that is populated by a value from another column in the same table where a flag is set to 'Y'. I can't seem to get the right syntax in M to get it to work. Can anyone help please? Example below. Thanks.

Time        Flag     Custom Column

07:30       N         07:45

07:45       Y          07:45

08:00       N         07:45

[AlB · Accepted solution]

Hi @markabdey 

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

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjC3MjY4tEBJR8lPKVYHzDcxBfMjIXwLKwO4fCwA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Time = _t, Flag = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Time", type time}, {"Flag", type text}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each #"Changed Type"{[Flag="Y"]}[Time], type time)
in
    #"Added Custom"

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.

[mahoneypat]

This would be easier with DAX but it can be done in the query editor too.  Will all rows have the same value in that column (as with your example), or are there other columns and the Y value within a group needs to be found?  If the latter, please update your example data to reflect that so you get what you need.

Pat

[markabdey]

Thanks for your reply. The value will be the same across all the rows.

[Fowmy]

@markabdey 

Click the Custom column and enter the following code:

=if [Flag] = "Y" then [Time] else null