Postgres 16

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CREATE TABLE public.parameterbased_return_table (
  col1 text
, col2 text
, col3 int4
, col4 int4
);

INSERT INTO public.parameterbased_return_table VALUES
  ('A', 'B', 11, 22)
, ('dfdf', 'dfe', 14, 545)
RETURNING *;

CREATE TABLE




col1
col2
col3
col4


A
B
11
22

dfdf
dfe
14
545



INSERT 0 2


CREATE OR REPLACE FUNCTION public.get_parameterbased_return_table(condition text)
  RETURNS TABLE (col1 text, col2 text)
  LANGUAGE plpgsql AS
$func$
BEGIN
   CASE condition
   WHEN 'condition1' THEN
      RETURN QUERY
      SELECT t.col1, t.col2
      FROM   parameterbased_return_table t;
   WHEN 'condition2' THEN
      RETURN QUERY
      SELECT t.col3::text, t.col4::text
      FROM   parameterbased_return_table t;
   ELSE
      -- Handle other conditions or return an empty result set
      RETURN QUERY
      SELECT NULL::record;
   END CASE;
END
$func$;

CREATE FUNCTION


SELECT * FROM public.get_parameterbased_return_table('condition1');


col1
col2


A
B

dfdf
dfe



SELECT 2


-- change (only) column names
SELECT * FROM public.get_parameterbased_return_table('condition2') AS t(col3, col4);


col3
col4


11
22

14
545



SELECT 2