Re: delete with self join
От | Thomas Burdairon |
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Тема | Re: delete with self join |
Дата | |
Msg-id | D02A5D1D-A9B6-49B0-AEEA-2FF21D9842BD@entelience.com обсуждение исходный текст |
Ответ на | Re: delete with self join (garry saddington <garry@schoolteachers.co.uk>) |
Список | pgsql-general |
On Apr 17, 2007, at 11:07, garry saddington wrote: >> > > I am keeping a record of siblings in a school. The user chooses one > student and there siblings such that id's are entered into a table as > such: > TABLE SIBLINGS: > > principal sibling > 809 234 > 809 785 > 809 345 > 809 809 > > 809 is a sibling of all of them, but of course 234 is a sibling of > 785. > To retrieve siblings I use this query: > > SELECT > students.studentid,students.firstname,students.surname,students.year,s > tudents.pastoralgroup,students.dob > FROM siblings c, siblings c2,students > WHERE c.principal = c2.principal > and c.sibling=234 (this value is supplied in a variable) > and c2.sibling=students.studentid > > What I am trying to do is to allow the user to correct input > mistakes by > deleting all the siblings of one family at the same time by choosing > just one of the siblings. I hope this clears things up. > Regards > Garry > What about a DELETE FROM siblings WHERE principal IN (SELECT principal FROM siblings WHERE sibling = 42) ? Thomas
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