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How would I store the result of a select statement so that I can reuse the results to join to different tables? This will also be inside a cursor.

Below is some pseudo code, in this example I have kept the Select statement simple but in real life it is a long query with multiple joins, I have to use the identical SQL twice to join to 2 different tables and as it is quite long and can be changed in the future hence I want to be able reuse it.

I have tried creating a view and storing the results of the select statement in it but it seems I can't create a view inside the cursor loop, when I tried I am getting "Encountered the symbol "CREATE"" error.

DECLARE TYPE cur_type IS REF CURSOR;
CURSOR PT_Cursor IS

    SELECT * FROM Table1

    PT_Cursor_Row   PT_Cursor%ROWTYPE;

BEGIN
 OPEN PT_Cursor;

 LOOP
    FETCH PT_Cursor INTO PT_Cursor_Row;
    EXIT WHEN PT_Cursor%NOTFOUND;

    Select ID From Table2 --this is actually a long complext query
        INNER JOIN Table3 ON Table2.ID = Table3.ID
    WHERE Table2.ID = PT_Cursor_Row.ID

    Select * From Table2 --this is actually a long complext query
        LEFT JOIN Table4 ON Table2.ID = Table4.ID
    WHERE Table2.ID = PT_Cursor_Row.ID                               

END LOOP;

 CLOSE PT_Cursor;
END; 
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IMO belongs on SO –  Yasir Arsanukaev May 31 '13 at 9:02
    
Umm, a view maybe? –  Colin 't Hart Jun 30 '13 at 16:18
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1 Answer

You may store the results you want to reuse into a nested table type. In the following example, I use a nested table of number(22,0). A nested table in PL/SQL is not a real table, it just exists in memory like an array.

-- Creating some test tables and data
create table table1 (row_id number(22,0));
create table table2 (row_id number(22,0));

insert into table1 values(1);
insert into table1 values(2);
insert into table1 values(3);
insert into table2 values(1);
insert into table2 values(2);

---------

-- Create a nested table type
CREATE OR REPLACE TYPE type_table_number AS TABLE OF NUMBER(22);

declare
 v_tab type_table_number;
 cursor c is
   select row_id
   from   table2
   where  row_id in (SELECT row_id FROM TABLE (v_tab));
begin
  -- Select row_ids into the table v_tab
  -- (this is not a real table, the data is stored in memory)
  select row_id
  bulk   collect into v_tab
  from   table1
  WHERE  row_id in (1,2);
  -- Select some data from a table and use the content
  -- of the in memory table (v_tab) as search criteria:
  for v_rec in c loop
    DBMS_OUTPUT.PUT_LINE(v_rec.row_id);
  end loop;
  -- Select some other data from another table and also
  -- use the same content of the in memory table:
  -- ...
END;
/
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