create [or replace] function function_name(param_list)
returns return_type
language plpgsql
as $$
declare
-- variable declaration
begin
-- logic
end;
$$
postgres=# Create or replace function fun1(n int) returns int
as
$$
Begin
Insert into test values (n,'2019-11-26');
Return 1;
End;
$$
Language 'plpgsql';
CREATE FUNCTION
postgres=#
