Question

The following PL/SQL successfully executes as expected:

declare
    myCount number;
begin
    select count(*)
    into myCount
    from myTable
    where id = 1;
end;

However, the following does not and instead throws this error:

ORA-01422: exact fetch returns more than requested number of rows

declare
    myCount number;
    myId number := 1;
begin
    select count(*)
    into myCount
    from myTable
    where id = myId;
end;

Conceptually, I understand what the error means, but I don’t know how it applies to my situation. All I’ve done is moved the hardcoded value to a variable in the declare block. Why would that affect the results of the select when it’s the exact same number?

Version is Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production.

Answer 1

There is something going on in your system that you haven’t reproduced in this question. If I create a table myTable in my local system, your code runs without error

SQL> create table myTable( id number );

Table created.

SQL> declare
  2      myCount number;
  3      myId number := 1;
  4  begin
  5      select count(*)
  6      into myCount
  7      from myTable
  8      where id = myId;
  9  end;
 10  /

PL/SQL procedure successfully completed.

Is it possible that there is some difference between the code you’ve posted and the code that you’re actually running?