Error Message : Query has no destination for result data - postgresql

Question

I am new to postgreSQL. I am trying to convert SQL store procedure into postgreSQL store function. I tried Like below store function created successfully but when I am trying to execute I am getting following error message. I am not getting where I need to replace PERFORM.
ERROR: query has no destination for result data
HINT: If you want to discard the results of a SELECT, use PERFORM instead.
SQL Store Procedure
CREATE PROCEDURE [dbo].[roomType]
#intInstId int
AS
BEGIN
SELECT
nClientRoomTypeID,sClientRTDesc,sClientRTName,sClientRTCode
FROM
ClientRoomType
WHERE
ClientRoomType.nInstID=#intInstId
ORDER BY
ClientRoomType.sClientRTCode
END
GO
PostgreSQl Store Function
CREATE OR REPLACE FUNCTION roomType (int_inst_id int)
RETURNS VOID
AS $$
BEGIN
SELECT
nclient_room_type_id,sclient_rt_desc,sclient_rt_name,sclient_rt_code
FROM
clientroomtype
WHERE
clientroomtype.ninst_id=int_inst_id
ORDER BY
clientroomtype.sclient_rt_code;
END;
$$ LANGUAGE plpgsql;

Answer 1

I assume you're attempting to return the query result with your function. You actually do not need plpgsql language for this, but in case you need it for somthing else, use this syntax:
CREATE OR REPLACE FUNCTION roomType (int_inst_id int)
RETURNS TABLE (res_nclient_room_type_id INT,res_sclient_rt_desc TEXT,res_sclient_rt_name TEXT, res_sclient_rt_code TEXT)
AS $$
BEGIN
RETURN QUERY
SELECT
nclient_room_type_id,sclient_rt_desc,sclient_rt_name,sclient_rt_code
FROM
clientroomtype
WHERE
clientroomtype.ninst_id=int_inst_id
ORDER BY
clientroomtype.sclient_rt_code;
END;
$$ LANGUAGE plpgsql;
How to use it?
SELECT * FROM roomType(1);
Since I do not have your data, I cannot test it. But it follows this principle:
CREATE OR REPLACE FUNCTION f ()
RETURNS TABLE (b boolean, x int)
AS $$
BEGIN
RETURN QUERY SELECT TRUE, 1;
END;
$$ LANGUAGE plpgsql;
SELECT * FROM f();
b | x
---+---
t | 1
(1 Zeile)