Re: Need SQL Help Finding Current Status of members
От | Richard Huxton |
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Тема | Re: Need SQL Help Finding Current Status of members |
Дата | |
Msg-id | 43A287C6.2090501@archonet.com обсуждение исходный текст |
Ответ на | Need SQL Help Finding Current Status of members ("Michael Avila" <Michael.Avila.1@sbcglobal.net>) |
Ответы |
Re: Need SQL Help Finding Current Status of members
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Список | pgsql-sql |
Michael Avila wrote: > I have a table which keeps track of the status of members. In the table is > > > member_id int(8) > status_code char(1) > status_date date > > KEY member_id (member_id,status_code,status_date) > > > Each member can have multiple records because a record is added each time > the status changes but the old record is kept for history. > > What I want to do is find the latest status for each member. Michael Fuhr has already described on solution, but if you can alter the table definition then there might be a neater solution. Replace "status_date" with "status_expires" and make it a "timestamp with time zone". Set the expiry to 'infinity' for the current record and you then have a simple select to find the mostrecent. If you regularly want to find which record was active on a particular time you'll want two columns: valid_from and valid_to. This makes it much easier to find a row for a specific date. -- Richard Huxton Archonet Ltd
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