Mapping columns can match/map, reorder or drop columns.
With the "Column Mapping" feature, the columns from Source A and B can be paired as needed, any unmatched element will be dropped from the data extraction.
The included matching actions should take care of the most common tasks as follows.
Match by column position: This will pair all columns in the order they came from the data source, this is ideal to revert changes.
Match columns by name: This will pair columns with the exact column name (This is NOT case sensitive).
How to re-gain dropped columns?
After performing a new data extraction a message will pop up asking if you want to keep using the custom mapping, by selecting "No" all columns for both data sources will be re-established. Please notice that, using the option to extract and compare as a single step will bypass this message.