Sergey Karin schrieb:
Hi, List!
I'm using PG8.1.
Are there any abilities to represent NULL values as string?
I'm doing something like this:
create function func(int4) returns varchar as'
declare
num_value alias for $1;
string_value varchar;
begin
string_value := \'input value = \' || num_value;
return string_value;
end
'language 'plpgsql';
If I einvoke my function with NULL argument, it return NULL. But I want
'input value = NULL'.
Of course, I can check input value like this:
if(num_value isnull) then
string_value := \'input value = NULL\';
else
string_value := \'input_value = \' || num_value;
end if;
You can use COALESCE()
create function func(int4) returns text as $$
declare
num_value alias for $1;
begin
return 'input value = ' || COALESCE(num_value,'NULL');
end
$$ language 'plpgsql';
(Id rather use more descriptive name for your function)
Regards
Tino
