Calling stored procedure - mysterious error

Question

Hi all,
I have a problem with one stored procedure.
The procedure looks like this simplified sample:
create or replace procedure sp_sample (
p_input1 in char,
p_input2 in number,
p_input10 in char,
p_in_out in out number
as
l_in_out number(38) := p_in_out;
begin
select count(t1.id_t1)
into l_in_out
from table1 t1
where
(field1 = p_input1) and
(field2 = p_input2) and
(field10 like p_input10);
p_in_out := l_in_out;
end;
And now the problem:
When I call the procedure in some PL/SQL block like this:
declare
l_cnt number(38);
begin
sp_sample(
p_input1 => 'ABC',
p_input2 => 2,
p_input10 => '%',
p_in_out => l_cnt
dbms_output.put_line(l_cnt);
end;
-> I receive the error message ORA-01722 in the first line of the select ("select count(t1.id_t1) ...").
But if I call the procedure in similar PL/SQL block like this:
declare
l_cnt number(38);
l_char char(10 char);
begin
l_char := '%';
sp_sample(
p_input1 => 'ABC',
p_input2 => 2,
p_input10 => l_char,
p_in_out => l_cnt
dbms_output.put_line(l_cnt);
end;
-> I receive a correct result.
The only difference is in the using of a local variable instead of a string literal!
When I simplified the conditions in the where clause in the select, the calling of the procedure passed always.
It seems the error is caused by complicated condition in the select and some mystery concerning of passing parameters into a procedure or binding variables.
Has anybody any experience like this?
Jiri

Answer 1

The old invalid number problem.
Its one of the following:
1) you are using implicit conversions
2) you have a misunderstanding of how the oracle optimizer works.
Probably 2, as the query works with the hardcoded literal but not the variable.
Basically, you are getting two separate query plans, ie oracle is using a different way of getting the result depending on whether it is using a literal or a variable.
Basically in one scenario, you are encountering a non-numeric character and an attempt is being made to convert this to a number.
In the other, you never encounter the non-numeric character