Filter operator: The addition EXCEPT is not the same as a negation of the WHERE condition

[philipsalve]

The documentation of the filter operator contains this note and does not elaborate or give examples.

The addition EXCEPT is not the same as a negation of the WHERE condition, particularly in the variant with a filter table.

Could someone please give an example where this is the case?

[fedaros]

Hi Philip,

What I remind about EXCEPT is to be used on result sets, in fact I prefer the SQL which support MINUS operator, which make more sense to me and works in same way. See discussion:

https://blogs.sap.com/2014/07/31/an-introduction-to-hana-s-except-set-operator-function/

Also see a example:

https://help.sap.com/docs/SAP_NETWEAVER_DBOS/798ce92dc90c47aa8dd1092c185c45df/44e302913ee203fce10000...

https://blogs.sap.com/2017/10/04/calculation-view-intersect-and-minus-nodes/

Regards, Fernando Da Rós

[Sandra_Rossi]

If I understand well your answer, I think that the question is about FILTER and EXCEPT in ABAP, not about database/SQL.

[fedaros]

That's correct sandra.rossi

This ABAP except is new for me.

[Sandra_Rossi]

The sentence "The addition EXCEPT is not the same as a negation of the WHERE condition, particularly in the variant with a filter table" is taken from here: ABAP Documentation - FILTER, Filter Operator (addition EXCEPT).

I don't understand too. According to me, the result is always the same, i.e.

itab = FILTER #( itab EXCEPT IN ftab WHERE c1 = f1 ).

would be equivalent to (this syntax is INVALID of course😞

itab = FILTER #( itab IN ftab WHERE NOT ( c1 = f1 ) ).

Let's see what people have to say...