Following is my sample function
create or replace function samp(in a int) returns int as
$$
declare
val int;
val1 int;
begin
select coalesce(a-1,1) into val,coalesce(a-2,1) into val1;
return val + val1;
end;
$$
language plpgsql
when executing it I get following error
ERROR: "coalesce" is not a known variable LINE 7: select coalesce(a-1,1) into val,coalesce(a-2,1) into val1;