Select into aggregate function

Question

Hi,
I have the following PL/SQL block that I am testing. The block reads a list of values from a local file and inserts the values into a select statement that uses an aggregate function. Here is my code:
DECLARE
f utl_file.file_type;
n COLa%TYPE; --holds values from the file
v COLb%TYPE; --holds value returned by select statement
BEGIN
f := utl_file.fopen(dir,file.txt,'R');
loop -- loop through file
     utl_file.get_line(f,n);
     if length(n) <> 0 then
          SELECT max(A0.COLa) into v
          FROM (SELECT AOB.COLa, A0.COLb
          FROM TAB1 A0,TAB2 A0B
          WHERE (A0.PK=A0B.PK) and A0B.COLa = n) A0;          
          IF SQL%rowcount = 0 THEN
               dbms_output.put_line('no rows);
          else
               dbms_output.put_line(v);
          end if;                    
     end if;     
end loop;
     utl_file.fclose(f);     
end;
Here is the error I get:
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at "SYS.UTL_FILE", line 98
ORA-06512: at "SYS.UTL_FILE", line 656
ORA-06512: at line 12
I checked the database for the first couple of values in the list and got rows. I also ran a simple PL/sql code to print values in the file successfully. So I dont know why it is returning no data found. From what I understand select into statement using aggregate functions will never raise this exception, so why I am getting this error?
Thanks.

Answer 1

Hi,
Actually, the SELECT ... INTO isn't the problem here.
Look at the error message:
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at "SYS.UTL_FILE", line 98
ORA-06512: at "SYS.UTL_FILE", line 656
ORA-06512: at line 12The error is ocurring inside utl_file, which is being called at line 12 of your code. (That must be
utl_file.get_line(f,n);)
Utl_file.get_line raises NO_DATA_FOUND when it reaches the end of the file. (If it didn't you'd have an infinite loop, since your code doesn't have any exit strategy.)
You can put the call to get_line in its won BEGIN-EXCEPTION-END block, and trap the NO_DATA_FOUND error.
For example:
end_of_file := 0;
WHILE  end_of_file = 0;
loop -- loop through file
    BEGIN
        utl_file.get_line(f,n);
        if length(n) != 0 then          -- Use !=, because you can't post &lt;&gt; on this site
            SELECT  max(A0B.COLa)     -- No sub-query needed
            into    v
            FROM    TAB1 A0
            ,         TAB2 A0B
            WHERE   (A0.PK   = A0B.PK)
            and         A0B.COLa = n;
            IF SQL%rowcount = 0 THEN     -- Not needed: SELECT MAX ... without GROUP BY always returns 1 row
                dbms_output.put_line('no rows);
            else
                dbms_output.put_line(v);
            end if;
        end if;
    EXCEPTION
        WHEN  NO_DATA_FOUND
        THEN
            end_of_file = 1;
    END;
end loop;Edited by: Frank Kulash on Jul 17, 2009 2:51 PM