Re: [HACKERS] "SELECT *" vs hidden columns and logical column order
От | Thomas Munro |
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Тема | Re: [HACKERS] "SELECT *" vs hidden columns and logical column order |
Дата | |
Msg-id | CAEepm=0+oDyCvC+Enqc271EsWPFtF0xqu3ZBQjkTwSNTKDQh-A@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: [HACKERS] "SELECT *" vs hidden columns and logical column order (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>) |
Список | pgsql-hackers |
On Sat, Jul 1, 2017 at 6:09 AM, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote: > On 6/28/17 23:52, Thomas Munro wrote: >> 2. SQL:2011 temporal tables track system time and/or valid time with >> columns that users create and then declare to be temporal control >> columns. I don't think they show up unless you name them directly (I >> didn't check the standard but I noticed that it's that way in another >> product), so I guess that's basically the same as (1). > > In my reading of the standard, those start/end time columns would show > up normally in SELECT *. Oh, well that's surprising. I don't have a recent enough SQL standard to hand, but I saw that a couple of popular RDBMSs with temporal support understand GENERATED ALWAYS AS ROW { START | END } [[ IMPLICITLY ] HIDDEN ] where that last bit controls whether SELECT * sees it. -- Thomas Munro http://www.enterprisedb.com
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