RE: Outer join question

---------- From: Guillermo Labatte[SMTP:labatteg@usa.net] Sent: Friday, February 13, 1998 5:28 AM I'm using Online 5.07 I issue the command ... select * from table_A,outer table_B where table_A.x=table_B.y into temp table_C; select * from table_C where y is null and it returns a different result from select * from table_A,outer table_B where table_A.x=table_B.y and table_B is null; Why? <RANT> Because it has always been defined to behave differently. I think the definition of OUTER JOIN is obnoxious, precisely because of this discrepancy, but I raised this issue a long time ago (5-10 years ago!), and it was defined that the observed behaviour was the correct behaviour by documenting it in a Tech Notes article. </RANT> In short, be very careful with OUTER joins because the behaviour you observe is defined to be correct but is anything but intuitive. My 'Using Informix-SQL' book tries to explain this. C J Date comments adversely on my description of it (and also the implementation I'm describing) in one of his 'Selected Writings' books (I think it's the 90-94 one). Yours, Jonathan Leffler (jleffler@visa.com) #include <sphinx.h>