When trying write a function in plpgsql I'm getting behavior that
probably isn't the corect one.
in the function bellow:
-----
-- split the given key
create function dad_char_key_split( varchar, -- char_key integer, -- subkey_len char
-- separator
) returns varchar as '
declare p_char_key alias for $1; p_subkey_len alias for $2; p_separator alias for $3;
v_key_len integer; v_from integer; v_result varchar; v_sep char;
begin v_result := ''''; v_sep := ''''; v_from := 1; v_key_len := char_length(p_char_key);
fori in 1..(v_key_len/p_subkey_len) loop v_result := v_result || v_sep ||
substr(p_char_key,v_from,p_subkey_len); v_sep := p_separator; v_from := v_from +
p_subkey_len; end loop; return v_result;
end;' language 'plpgsql';
----
if I try this:
select dad_char_key_split('00kjoi',2,',');
I get this result:
",kj,oi"
And when I change the initialization of the variables "v_sep" and
"v_result" from empty strings to a space ('' '' istead of '''') I get
the expected result:
"00,kj,oi"
It seems that plpgsql treats empty strings as null so when concatenating
with a empty string we get null instead of some value.