I just do this as a standard every time. No surprises that way.
Dennis McGrath Software Developer QMI Security Solutions 1661 Glenlake Ave Itasca IL 60143 630-980-8461 [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Karen Tellef Sent: Monday, December 09, 2013 9:08 AM To: RBASE-L Mailing List Subject: [RBASE-L] - Re: DELETE DUPLICATES, Setting: SET EQNULL OFF Yes this is the expected result. If you think any of the columns might have nulls in them, then you have to SET EQNULL ON first before you do the delete, then SET EQNULL OFF when you're done. Karen -----Original Message----- From: Dr. Fritz Luettgens <[email protected]<mailto:[email protected]>> To: RBASE-L Mailing List <[email protected]<mailto:[email protected]>> Sent: Sun, Dec 8, 2013 4:28 am Subject: [RBASE-L] - AW: [RBASE-L] - Re: DELETE DUPLICATES, Setting: SET EQNULL OFF Understood, but one finalizing question: A B C 1 1 1 1 1 1 -0- 2 2 -0- 2 2 Still: EQNULL: OFF DELETE DUPLICATES FROM TAB USING A, B, C Result: first 2 rows are removed, row 3 and 4 not. Problem: the .. USING extension does not solve the problem in big tables either Consequence: incl. the settings before the command for now ... SET EQNULL ON DELETE DUPLICATES FROM tab --DELETE DUPLICATES FROM tab USING A,B, C SET EQNULL OFF with very best regards Fritz -----Ursprüngliche Nachricht----- Von: [email protected]<mailto:[email protected]> [mailto:[email protected]<mailto:[email protected]?>] Im Auftrag von A. Razzak Memon Gesendet: Sonntag, 8. Dezember 2013 00:43 An: RBASE-L Mailing List Betreff: [RBASE-L] - Re: DELETE DUPLICATES, Setting: SET EQNULL OFF At 06:18 PM 12/7/2013, Dr. Fritz Luettgens wrote: >In my table not all colums have values, but duplicates exist. >My standard setting is: SET EQNULL OFF, NULL: -0- I want: DELETE >DUPLICATES FROM TABLE result is: 0 duplicates have been deleted but >when: SET EQNULL ON the command is successful: n duplicates have been >deleted ! >Question: Should this command not also work on a table with setting SET >EQNULL OFF ? Dr. Fritz, Here's a technical explanation ... When using the DELETE DUPLICATES command without specifying the "USING columnname", all matching rows and columns, including the columns with NULL values are evaluated. The EQNULL setting as TRUE (ON) means that a comparison between two NULL values is a match and that a comparison between a NULL value and a non-NULL value is not. When EQNULL is set to FALSE (OFF) then a comparison between two NULL values is not a match nor is a comparison between a NULL value and a non-NULL value a mismatch. The NULL value essentially make the whole thing "unknown'. Hope that helps you understand the difference. If you need a few examples to understand this whole thing practically, feel free to reach out to me with further questions. Very Best R:egards, Razzak. www.rbase.com<http://www.rbase.com> www.facebook.com/rbase<http://www.facebook.com/rbase> -- 30+ years of continuous innovation! 15 Years of R:BASE Technologies, Inc. making R:BASE what it is today! --
