AW: XML column causes record to be both NULL and NOT NULL
От | Wilm Hoyer |
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Тема | AW: XML column causes record to be both NULL and NOT NULL |
Дата | |
Msg-id | 462567f501af4621964bccacaf824590@dental-vision.de обсуждение исходный текст |
Ответ на | Re: XML column causes record to be both NULL and NOT NULL (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-bugs |
> Well, it is strange, but it's acting per SQL spec. > As stated at [1]: >> If the expression is row-valued, then IS NULL is true when the row >> expression itself is null or when all the row's fields are null, while >> IS NOT NULL is true when the row expression itself is non-null and all >> the row's fields are non-null. Because of this behavior, IS NULL and >> IS NOT NULL do not always return inverse results for row-valued >> expressions; in particular, a row-valued expression that contains both >> null and non-null fields will return false for both tests. > The fact that the added column is of XML type isn't relevant here; what's relevant is that it has a null value. > regards, tom lane > [1] https://www.postgresql.org/docs/current/functions-comparison.html Thanks for the Explanation. The solution is clear then - just test part of the record or "flatten" the record with a castto text. Best regards, Wilm.
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