Union All

Union all concatenates tables together. For example, if I have a table for every state, I could concatenate them into one table for the whole country.

UNION ALL WITH table1, table2, ...;

The schema of each table is carried into the unioned table; no attribute is dropped. If the initial schemas match, then the unioned table will have the same exact schema. If there is an attribute in one schema that is different, then the unioned table will include it at the end of the schema.

❗️
Matching attributes must have matching types
If the schemas have a matching attribute, the attribute must be the same type in each schema for them to be unioned correctly.

For example, let's say I have a Massachusetts and Vermont table with resident information.

Massachusetts.csv:

ID	Name	Surname
002	John	Smith
003	Sarah	Brown
004	Alex	Jones

Vermont.csv:

First_Name	Surname
Abby	Elliot
Ben	Anderson
Carol	Baldwin

If I want to union these two tables together, I tell the Transformation System to first use Massachusetts.csv and concatenate with Vermont.csv:
Use Massachusetts.csv; UNION ALL WITH Vermont.csv

My unioned table will look like:

ID	Name	Surname	First_Name
002	John	Smith
003	Sarah	Brown
004	Alex	Jones
		Elliot	Abby
		Anderson	Ben
		Baldwin	Carol

❗️Matching attributes must have matching types

❗️
Matching attributes must have matching types