Appending Tables with Non-Matching Columns
You can create Unions with tables with similar data from different systems but you may need to create some default values for columns that do not map to each other.
For example, another system may capture city but not region and you want to create a Union with a table that captures both City and Region. You could enter a default value for the table that lacks the Region data so it can map to the Region column as desired.
You cannot create Unions with columns that contain similar data but different data types.