sql - function result type must be integer because of OUT parameters in postgresql -

in below query when execute throws error function result type must integer because of out parameters.pls me overocme issue.

create or replace function funinsertupdateproduct(i_productid integer, t_productname text, t_productdesc text, i_brandid integer, i_varianceid integer, i_packsizeid integer, i_clientid integer, i_userid integer,out i_prodid integer )   returns void  $body$  begin      if exists (select 1  "product" product_id = i_productid)         update "product" set "product_name" = t_productname,  "product_desc" = t_productdesc, "brand_id"=i_brandid,variance_id=i_varianceid,pack_size_id=i_packsizeid  product_id = i_productid;     else         insert "product"("product_name", "product_desc", "create_by","client_id",variance_id,brand_id,pack_size_id ) values (  t_productname, t_productdesc,i_userid,i_clientid,i_varianceid,i_brandid,i_packsizeid) returning product_id i_prodid;  end if;   return; end;   $body$   language plpgsql volatile   cost 100; alter function funinsertupdateproduct(integer, text, text, integer, integer, integer, integer, integer,integer) owner postgres; 

postgres functions take getting used to. in addition being triggers , stored procedures, way handled returned values differs other languages.

in essence, out parameters represent record being returned function. there no separate method of returning value, void redundant . . . and, in fact, incompatible out parameters.

the solution simple. remove returns clause:

create or replace function funinsertupdateproduct (     i_productid integer,     t_productname text,     t_productdesc text,     i_brandid integer,     i_varianceid integer,     i_packsizeid integer,     i_clientid integer,     i_userid integer,     out i_prodid integer ) $body$  . . .  

except not defining i_prodid, equivalent to:

create or replace function funinsertupdateproduct (     i_productid integer,     t_productname text,     t_productdesc text,     i_brandid integer,     i_varianceid integer,     i_packsizeid integer,     i_clientid integer,     i_userid integer )  returns integer $body$  . . .