Question

Using Oracle 11
I’m wanting to pull data from a table, and add a column of calculated values which come from a subquery statement.

Example Table1 is:

COLUMN1:   COLUMN2:
1          Group1
3          Group2
5          Group3
6          Group4

The subquery returns different values each time the query is run, but for the sake of this example let’s say it returns thes values:

2
4
7
8

What I need is to combine the results

COLUMN1:   COLUMN2:    COLUMN3: (subquery - order does NOT matter)
1          Group1      2
3          Group2      4
5          Group3      7
6          Group4      8

But because the subquery is being calculated with each row return from the table, all I am getting is.

COLUMN1:   COLUMN2:    COLUMN3: 
1          Group1      2
3          Group2      2
5          Group3      2
6          Group4      2

There is no way that I can think of to relate the table and the subquery, I’ve tried playing with ROWNUM but with no luck.

UPDATE

SELECT GD.*, N
  FROM patrongroupsdesc GD,
       (SELECT n
          FROM patrongroupsdesc GD2,
               (SELECT n, ROWNUM
                  FROM (    SELECT ROWNUM n
                              FROM DUAL
                        CONNECT BY LEVEL <= 100)
                 WHERE n >= 1) SUB
         WHERE SUB.n = GD2.groupid(+) AND GD2.groupid IS NULL) SUB2

table PATRONGROUPSDESC is formatted as follows

groupid (NUMBER)
description (VARCHAR2)
...other data

SUB returns the values 1-100
SUB2 returns the gaps in groupid numbers
I’m essentially duplicating all data in this table except for one column

Answer 1

First you must know that if you don’t have an ORDER BY clause then the order of the results comes with no guarantee at all.

Then, you can do:

WITH first_table AS (select *, ROWNUM AS rn FROM ...)
   , secnd_table AS (select *, ROWNUM AS rn FROM ...)
SELECT first_table.*, secnd_table.*
  FROM first_table INNER JOIN secnd_table USING (rn)

The trick here is that ROWNUM is assigned as a result comes out from a SELECT statement. Therefore if you want to paste tables like this, you must SELECT from your tables and store rownum in another column, and then from those two subselects you can join.