Re: Is this a feature ?
От | Nick Fankhauser |
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Тема | Re: Is this a feature ? |
Дата | |
Msg-id | NEBBLAAHGLEEPCGOBHDGIEBLFBAA.nickf@ontko.com обсуждение исходный текст |
Ответ на | Is this a feature ? (David BOURIAUD <david.bouriaud@ac-rouen.fr>) |
Ответы |
Re: Is this a feature ?
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Список | pgsql-sql |
> if one of the fields (civ, name or forname) is null, identity is > null... That doesn't seems right, since it means that 1+2+0 = 0 !!!! The crux of the matter is that zero and null aren't the same thing. Null means in essence "We don't know", so this equation is better writtin as: 1+2+"don't know" = "don't know" > is there a > way to work > this around ? It *is* often true that when concatenating strings, we want to tell SQL "if this value is null, treat it like an empty string". This is how you would do it: coalesce( civ,'')||coalesce(name,'')||coalesce(forname,'') Regards, -Nick
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