Comments on: How to generate multiple rows from a single row based on a date range

By: Laurent Schneider

Laurent Schneider — Thu, 06 Mar 2008 07:32:04 +0000

about the ORA-1436 please monitor enhancement request 6801807 on metalink

By: stewstryker

stewstryker — Fri, 04 Jan 2008 01:01:05 +0000

Thanks for the reply. I tried about 8 times using various interfaces and always got the same error. Oh well!

By: Laurent Schneider

Laurent Schneider — Thu, 03 Jan 2008 21:57:11 +0000

try to run in more than once and you will see it works sometimes.

about the error manual, I have reported that to the doc owner, good catch!

By: stewstryker

stewstryker — Thu, 03 Jan 2008 21:25:44 +0000

Hmm, when I try Laurent’s version:

select rownum from dual connect by level < 3
   and prior trunc(dbms_random.value(1,3)) is not null;

I get the error:

ORA-01436: CONNECT BY loop in user data

Strangely, I can’t find that error in the manual… We’re running 10.2.0.3.0

[sigh]

By: Laurent Schneider

Laurent Schneider — Wed, 21 Mar 2007 12:46:08 +0000

the < did not work, here again with <

select rownum from dual connect by level < 3 and prior trunc(dbms_random.value(1,3)) is not null;

By: Laurent Schneider

Laurent Schneider — Wed, 21 Mar 2007 12:44:24 +0000

well, connect by without prior is not supported. But using connect by prior dbms_random.value is not null is not fair. First it may fail anytime, like the following query works 50% of the time

select rownum from dual connect by level 

(of course yours works 99.99% )

what's more, it is such a hack that I would never rely on it. The optimizer may change the plan and it may suddenly fail in a next patchset. 

Actually, I would prefer to have ORA-1436 in any connect by without prior, but we will have to wait 12gR2 to see it ;-)

By: mkapadia

mkapadia — Wed, 14 Mar 2007 14:41:43 +0000

..continuation from previous query:

CONNECT BY LEVEL

By: mkapadia

mkapadia — Wed, 14 Mar 2007 14:38:29 +0000

SELECT TO_CHAR(ADD_MONTHS (start_year, (12 * r) – 12), ‘YYYY’) my
FROM (
SELECT TRUNC (start_date, ‘YEAR’) AS start_year, TRUNC
(end_date, ‘YEAR’) AS end_year,
TO_CHAR (TRUNC (end_date, ‘YEAR’), ‘YYYY’) –
TO_CHAR (TRUNC (start_date, ‘YEAR’), ‘YYYY’) + 1
AS yr
FROM t2
ORDER BY start_date, end_date
) a,
(SELECT LEVEL r
FROM DUAL
CONNECT BY LEVEL