On Wednesday 17 June 2009 19.08:10 klaus wrote: > ... whether a query will yield any result ...
> The best approximation > seems to be > query.first() is not None > which can select a lot of columns. I often see > query.count() > 0 > which can become quite expensive on a DBMS like PostgreSQL. Just a side note that pg tends to compute first() efficiently if (and I assume sa does this) the implementation uses LIMIT to tell the db that really only the first row is interesting. I don't know about other databases. cheers -- vbi -- this email is protected by a digital signature: http://fortytwo.ch/gpg
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