Functions which use an argument to decide which table to read

Hello,

I am trying to write a function which takes an argument and uses that
argument to return a set of rows from a table with the name given (or
possibly inferred) from the argument.

Example

CREATE TABLE test_1 (id SERIAL PRIMARY KEY, name TEXT);

CREATE TABLE test_2 (id SERIAL PRIMARY KEY, name TEXT, live BOOLEAN, other
VARCHAR);

CREATE TABLE test_3 (id SERIAL PRIMARY KEY, name TEXT, number DOUBLE
PRECISION);

Now the function in concept would be

function getData(which_table TEXT)

BEGIN

RETURN SELECT * FROM "which_table"

END

Or ideally

function getData(table_num INTEGER)

BEGIN

tblName := test_ || table_num;

RETURN SELECT * FROM test_"which_num";

END

It's important to note the 3 tables have a different structure and the case
I am trying to cater for is that the user doesn't know in advance what that
table structure is.

I tried

CREATE OR REPLACE FUNCTION getTest(mytable TEXT)

RETURNS SETOF RECORD AS

$$

DECLARE

result mytable%rowtype;

BEGIN

FOR result IN SELECT * FROM mytable

LOOP

RETURN NEXT result;

END LOOP;

RETURN;

END

$$ LANGUAGE plpgsql;

Obviously mytable is not a real table I would like to use a table whose name
is specified in the variable mytable.

Does anyone have any advice if this is even possible and what I should be
looking at to get there or to do instead?

Thanks in advance for any possible help

--

Jonathan Harden

Zen Internet Ltd