The following query (reduced to the bare maximum) was running perfectly in 10.2.0.4 WITH det AS (SELECT p.col_pk, p.dat_col FROM Table_a p LEFT JOIN Table_b j ON j.col_pk = p.col_pk AND j.dat_col = p.dat_col LEFT JOIN Table_c s ON s.col_pk = p.col_pk AND s.dat_col= p.dat_col WHERE p.dat_col = pid_dat_col AND p.col_pk = pin_col_pk AND (col_pk IS NOT NULL OR s.col_pk IS NOT NULL) ----> focus here and ((ln_in_num = 0 and (j.appl_org = 'X27' or (s.appl_org = 'X27' and j.col_pk is null) ) ) or ln_in_num = 1 ) ) SELECT p.col_pk, p.dat_col, p.ord_no FROM det JOIN Table_a p ON det.col_pk=p.col_pk AND det.dat_col=p.dat_col ; Until we have upgraded to 11.0.2.3 where it started crashing with ORA-00918: column ambiguously defined The solution has been to change the query by adding the appropriate alias as shown below: WITH det AS (SELECT p.col_pk, p.dat_col FROM Table_a p LEFT JOIN Table_b j ON j.col_pk = p.col_pk AND j.dat_col = p.dat_col LEFT JOIN Table_c s ON s.col_pk = p.col_pk AND s.dat_col= p.dat_col WHERE p.dat_col = pid_dat_col AND p.col_pk = pin_col_pk AND (*j*.col_pk IS NOT NULL OR s.col_pk IS NOT NULL) ----> focus here and ((ln_in_num = 0 and (j.appl_org = 'X27' or (s.appl_org = 'X27' and j.col_pk is null) ) ) or ln_in_num = 1 ) ) SELECT p.col_pk, p.dat_col, p.ord_no FROM det JOIN Table_a p ON det.col_pk=p.col_pk AND det.dat_col=p.dat_col ; Best regards Mohamed Houri www.hourim.wordpress.com 2013/10/16 Kim Berg Hansen <kibeha@xxxxxxxxx> > Nah, I did write "yet" - meaning that I personally have not bumped into > ANSI problems on 11.2 yet - I did not state that it was all good and fixed > ;-) I just meant ANSI syntax in 11.2 is at least a good deal better in 11.2 > than it was in version 10 (in my experience - I cannot speak for everyone > ;-) > > > > > On Wed, Oct 16, 2013 at 1:53 PM, Jonathan Lewis < > jonathan@xxxxxxxxxxxxxxxxxx > > wrote: > > > > > Is that a challenge ? > > > > ________________________________________ > > From: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] on > > behalf of Kim Berg Hansen [kibeha@xxxxxxxxx] > > Sent: 16 October 2013 12:28 > > To: ftilly@xxxxxxxxxxxxxx > > Cc: oracle-l@xxxxxxxxxxxxx > > Subject: Re: SQL has me confused. > > > > so now (on 11.2) I have not yet met trouble with ANSI stylesyntax :-) > > > > > > Regards > > > > > > Kim Berg Hansen > > > -- > //www.freelists.org/webpage/oracle-l > > > -- Bien Respectueusement Mohamed Houri -- //www.freelists.org/webpage/oracle-l