Pandu Poluan, 12.12.2011 05:39:
> Hello!
>
> Due to some legacy apps, I end up with two tables with similar information, but with zero intersection (i.e., both tables are exclusive of each other).
>
> For illustration:
>
> table_one has the fields emp_id and fullname
>
> table_two has the fields employee_id, first_name, and last_name
>
> Now, I need a query that will search for employee ID in both tables and return his/her full name.
>
> How do I do that? Will a simple UNION suffice?
Yes a UNION should do (actually a UNION ALL as it will not try to remove duplicates which makes the query faster)
select *
from (
select emp_id, fullname
from table_one
union all
select employee_id,
first_name||' '||last_name
from table_two
) t
where emp_id = 1