Forum Discussion
Comparing values from two columns and write result in third one
In the query-editor (!) you can add a column with this formula:
List.Contains(NameOfThePreviousStep[ID1], [ID2])
This will check, if the value of the current row from column "ID2" matches any occurances within column "ID1". In order to search the whole column "ID1", you need to prefix it with the name of the previous step in your query.
This is a sample code, which demonstrates it if you paste it into the advanced editor:
let Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSAeJYnWglIyDLWCk2FgA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [ID1 = _t, ID2 = _t]), ChgType = Table.TransformColumnTypes(Source,{{"ID1", Int64.Type}, {"ID2", Int64.Type}}), #"Added Custom" = Table.AddColumn(ChgType, "Exists", each List.Contains(ChgType[ID1], [ID2])) in #"Added Custom"
Community ChampionImkeFthis is a very nice lookup code.
You are using this code to compare two columns within same table. Is it possible to use List.Contains to lookup ID1 column in table 1 to ID2 in table 2 by any chance.
Community ChampionIt would work like this:
List.Contains(NameOfTheQuery[ID1], [ID2])
But it might be slow on large tables.
Instead you can merge the 2 tables and instead of expanding the merged column, create a new one where you check if the merged column is empty or not:
Table.IsEmpty([MergedColumn])
This will return a true/false-column.