simple problem???
От | ivan marchesini |
---|---|
Тема | simple problem??? |
Дата | |
Msg-id | 1153407157.5192.64.camel@geoivan обсуждение исходный текст |
Ответы |
Re: simple problem???
Re: simple problem??? |
Список | pgsql-sql |
Dear users.... It's a simple problem I think (and I hope :-) I have a table like this: A|B|C 1|2|20 1|3|10 1|4|21 2|3|12 2|4|22 3|4|23 where the first two column are a combination without repetition (with k=2) of the numbers 1,2,3,4 for each pair I have a value in the column C. I would want a select that can extract these records: 1|3|10 2|3|12 3|4|23 i.e. the select must look into the A field first and: -select all records where A=1, -find, into this selection, the record where there's the minimum value of the field C -print all the fields for this record. then -select all records where A=2 -find, into this selection, the record where there's the minimum value of the field C -print all the fields of this record. and so on... using SELECT a,MIN(c) FROM table GROUP BY a is a partial solution because I can't see the value of B and I obtain: 1|10 2|12 3|23 How can I do for plotting also the value of B??? Thank you very much Ivan -- Ivan Marchesini Department of Civil and Environmental Engineering University of Perugia Via G. Duranti 93/a 06125 Perugia (Italy) e-mail: marchesini@unipg.it ivan.marchesini@gmail.com tel: +39(0)755853760 fax: +39(0)755853756 jabber: geoivan73@jabber.org
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