Re: SELECT mit NOT EXISTS
Problems with the requirement ...
- it refers to a status column but your DDL doesn't mention such a column
- it asks for person_ids ...
where group_id=1 with status=1
and group id=4 with status=0
AND group_id=1 and status=1 and not exists(group_id=4)
... implying that persons may belong to multiple groups, is that what's meant?
Also re the DDL, a Primary Key is by definition unique, so your person and gruppen table Unique keys are entirely redundant; and a Primary Key is obviously a key, so the gruppenzuordnung key(person_id) is also entirely redundant.
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Re: SELECT mit NOT EXISTS
May 13, 2020 06:56PM
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