I have multiple excel files, and i’m trying to read them and storing them in DataTables with Use excel file, then after I want to join the data tables based on common columns ( I have four excel files). after joining step, I have to store the joined output in a excel file that exists already. I tried to buid this process but it keeps returning this error:
“Join Data Tables: Argument value ‘Column Name’ is not set or is invalid.”
eventhough the column names that I set in the join activity exist in tables
Hi @imane.bousaad ,
Would suggest you to remove the existing values configured in the Join Datatables activity and re-type the column names that you would want to join.
Make sure that you type the column names and not Copy-Paste. When performing copy paste, there maybe irregular characters getting added up as well.
Once you confirm us that this also produces the same error, we can ask you to provide a Screenshot of the Configured activity and also Parallel Check by Debugging the column names in the Datatable.
Hi @supermanPunch
II already retype the column names, and it didn’t work
this is the config of joining :

@imane.bousaad ,
Was a Debug done and checked if the Column names are the same in the Datatables ?
@supermanPunch I verified it and now the joining problem is resolved, but what about if I want to store the joined data in an excel file that exists already respecting the layout and the order of headers
@imane.bousaad ,
We can pre-define/keep the column order as a String array at the beginning and then use this array to preserve only the required Columns in the Output by using DefaultView.ToTable() method.
columnNamesOrder = {"Column1Name","Column2Name",...}
DT = DT.DefaultView.ToTable(false,columnNamesOrder)
Let us know if the above approach is understandable.