Compile query results into a table

Hi,

I need to create a function in PostgreSQL for the following :

- Query multiple tables based on a business logic (all result sets return
the same type of data)

- Compile all result sets into one table and return that table

Is it possible to accomplish this without using the temp tables in
PostgreSQL?

Below is how I currently do it in Microsoft SQL server.

Sample function:

---------------------------------------------------

create FUNCTION test(@search_in nvarchar(500))

RETURNS @data_table TABLE

( item_id int, item_type nvarchar(1), first_name
nvarchar(100), last_name nvarchar(100))

AS

BEGIN

-- from first table

if charindex('search_in_authors', @search_in) > 0

insert into @data_table

select item_id, 'a',
first_name, last_name

from authors

where first_name = 'james'

-- from second table

if charindex('search_in_editors', @search_in) > 0

insert into @data_table

select item_id, 'e',
first_name, last_name

from editors

where first_name = 'james'

-- from third table

if charindex('search_in_publishers', @search_in) > 0

insert into @data_table

select item_id, 'p',
first_name, last_name

from publishes

where first_name = 'james'

-- there could be more like these based on the business
logic...

(...)

-- finally return the records compiled in @data_table

RETURN

END

-----------------------------------------------------

Sample calls to the function:

// select * from dbo. test ('search_in_authors')

// select * from dbo. test ('search_in_authors, search_in_editors')

// select * from dbo. test ('search_in_authors,
search_in_editors,search_in_publishers ')

-----------------------------------------------------

Are there any options in PostgreSQL to achieve this other than using a
temp table ?

Thanks,
Santosh