You can combine the results of two identically structured queries with the UNION keyword.

For example, if you wanted a list of all contact info from two separate tables, authors and editors, for instance, you could use the UNION keyword like so:

select name, email, phone_number 
from authors

union

select name, email, phone_number
from editors

Using union by itself will strip out duplicates. If you needed to keep duplicates in your query, you could use the ALL keyword like so: UNION ALL.