Re: SQL Diff ?
От | Ron Johnson |
---|---|
Тема | Re: SQL Diff ? |
Дата | |
Msg-id | 46D0EF1B.6010303@cox.net обсуждение исходный текст |
Ответ на | SQL Diff ? (Kevin Kempter <kevin@kevinkempterllc.com>) |
Ответы |
Re: SQL Diff ?
|
Список | pgsql-general |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/25/07 21:51, Kevin Kempter wrote: > Hi List; > > I have a very large table (52million rows) - I'm creating a copy of it to rid > it of 35G worth of dead space, then I'll do a sync, drop the original table > and rename table2. What is your definition of "dead space"? Bad rows, duplicate rows, old rows? Something else? > Once I have the table2 as a copy of table1 what's the best way to select all > rows that have been changed, modified in table1 since the initial laod from > table1 into table2? > > Also I'll need to delete any rows in table2 that no longer remain in table1. > > There is no change date column > I could do something like select * from table1 where col1 || col2 || col3 etc > not in (select col1 || col2 || col3 etc from table2) > > but this would be ineffecient & slow. > > Anyone have a suggestion to do this in an efficient manner? > > Thanks in advance - -- Ron Johnson, Jr. Jefferson LA USA Give a man a fish, and he eats for a day. Hit him with a fish, and he goes away for good! -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFG0O8bS9HxQb37XmcRAsWdAJoDI/WvdaGSO7CUkUa74xHoRgycIwCguLXv Msw0TdJyYI4keoq+ofu4j3c= =Gi/f -----END PGP SIGNATURE-----
В списке pgsql-general по дате отправления: