Parse data before import to dataset

HI mdobrescu,

According to your description, I'd like to suggest you can add a custom query step with an if statement to check the data source fields. Then use the current result or try to use add column function to add these missed columns.

Table.ColumnCount - PowerQuery M | Microsoft Docs

Table.AddColumn - PowerQuery M | Microsoft Docs

    Source = xxxxxx,
    Custom=
        if Table.ColumnCount(Source) > 2 then
            Source
        else
            Table.AddColumn(
                Source,
                "column2",
                each null
            )
in
    Custom

Regards,

Xiaoxin Sheng