A Wednesday 16 September 2009 17:19:15 escriguéreu: > There is one big downside though. My Two keys are field_name and > symbol_name. When I add tables/groups for field_name/symbol_name, I can > walkgroups and quickly found out what the unique field_names and > symbol_names are in the file. However, if I have 10 million plus rows+, is > there a sql equivalent of 'distinct' which will give me what the unique > field_names and symbol_names are in the table (assuming that both > field_names and symbol_names are indexed columns) without having to load > all the rows?
No, there is not a SQL 'distinct' equivalent right-out-of-the-box, but you could make use of the ``Table.readSorted()`` (or ``Table.iterssorted()``, its iterator counterpart) method in order to quickly locate the unique keys. Cheers, -- Francesc Alted ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Pytables-users mailing list Pytables-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pytables-users
