How do I loop through tables, not columns in a table?

Question

Sorry if this is a long one. My problem is actually quite simple. I am trying to write either an ad hoc PL/SQL block or a stored procedure to loop 18 times (thru 18 tables) and perform a SQL query on those tables, returning 18 resultsets. I would like the results to show up on the screen (or in a spool file, whatever).
So far I have tried 3 different approaches, none of which have worked.
1. I tried to assign the select query to a variable (qry) and use EXECUTE IMMEDIATE qry. This forced me thru a variety of errors to declare variables and assign the result to them--EXECUTE IMMEDIATE qry into nm0, nm1, nm2...
The problem with that was the resultset returned more than the variable was built for as there might be no rows returned, or it might be a thousand rows of data. So I tried changing the variables to VARRAYS, but it gave me a type mismatch as the underlying columns were NUMBER and VARCHAR2.
DECLARE
     ctr number;
     TYPE NUMLIST IS VARRAY (1000) OF NUMBER;
     TYPE VARLIST IS VARRAY (1000) OF VARCHAR2(15);
     nm0 NUMLIST NOT NULL DEFAULT 1;
     nm1 VARLIST;
     nm2 NUMLIST NOT NULL DEFAULT 1;
     nm3 VARLIST;
     nm17 NUMLIST NOT NULL DEFAULT 1;
     qry VARCHAR2(2000) := 'klx_uln_p000_cells';
BEGIN
FOR ctr IN 1..17 LOOP
     IF ctr < 10 THEN
          qry := 'SELECT
          A.DIM_0_INDEX,
          S0.SYM_NAME,
          A.DIM_1_INDEX,
          S1.SYM_NAME,
          A.DIM_2_INDEX,
          S2.SYM_NAME,
          A.DIM_3_INDEX,
          S3.SYM_NAME,
          A.NUMERIC_VALUE,
          B.NUMERIC_VALUE
          FROM
          KHALIX.klx_uln_p00'||ctr||'_cells A,
          KHALIX.klx_ucn_p00'||ctr||'_cells B,
          KHALIX.KLX_MASTER_SYMBOL S0,
          KHALIX.KLX_MASTER_SYMBOL S1,
          KHALIX.KLX_MASTER_SYMBOL S7
          WHERE
          A.DIM_0_INDEX=B.DIM_0_INDEX AND
          A.DIM_1_INDEX=B.DIM_1_INDEX AND...
          A.DIM_7_INDEX=S7.SYM_INDEX';
     ELSE
          qry := 'SELECT
          A.DIM_0_INDEX...
          A.DIM_7_INDEX=S7.SYM_INDEX';
     END IF;
     BEGIN
     dbms_output.put_line('SELECT FOR KLX_ULN_P00'||ctr||'_CELLS');
     dbms_output.put_line(nm16);
     dbms_output.put_line(nm17);
     EXECUTE IMMEDIATE qry into nm0,nm1,nm2,nm3,nm4,nm5,nm6,nm7,nm8,nm9,nm10,nm11,nm12,nm13,nm14,nm15,nm16,nm17;
--     dbms_output.put_line(qry);
     dbms_output.put_line(nm16);
     dbms_output.put_line(nm17);
     EXCEPTION
          WHEN NO_DATA_FOUND THEN
               dbms_output.put_line('No data found for Query '||ctr);
     END;
END LOOP;
EXCEPTION
     WHEN NO_DATA_FOUND THEN
          dbms_output.put_line('No data found for Query '||ctr);
END;
2. So then I used REF CURSOR to create a stored procedure and return the values. That allowed me to run my query AND tokenize the tablenames with a counter so that it would loop through the different tables! However, I still could not get it to display the results without going to SQL Plus and typing 'print c;'.
3. So, finally I tried to create a looping wrapper around the ref cursor to have some variable (ctr) increment so my query would get performed on table0_cells through table17_cells. This, too, did not work.
If I manually go to SQL Plus and type:
variable ctr number
begin
:ctr := 1;
end;
exec dupe_find(1,:c);
it will execute for the first table (klx_uln_p001_cells) and I can then type 'print c' to see what was returned. But when I try putting this within a wrapper PL/SQL block with a Loop to make ctr go from 0 - 17 (to loop through table_names klx_uln_p000_cells to klx_uln_p017_cells), it does not work.
Help! It should be very simple to loop through tables, shouldn't it? I just want a script that will loop through tables, perform a query on each table and display the results. For some reason, I can only find documentation examples on looping through columns that are all in the same table.
Dave

Answer 1

Here's a working example using your first strategy ...
create table t1 (id number);
create table t2 (id number);
insert into t1 values (100);
insert into t1 values (101);
insert into t2 values (200);
insert into t2 values (201);
declare
v_table_name user_tables.table_name%type;
type ttab_id is table of t1.id%type index by binary_integer;
tab_id ttab_id;
begin
for i in 1 .. 2 loop
v_table_name := 't' || i;
execute immediate 'select id from ' || v_table_name
bulk collect into tab_id;
dbms_output.put_line('query from ' || v_table_name);
for j in 1 .. tab_id.count loop
dbms_output.put_line(tab_id(j));
end loop;
end loop;
end;
There are many other ways to do this (especially if you need to do more than just print out the data).
Richard