Jay Thorne writes: > > Okay, now I need an example. I've never seen a query on any db where a single > table query was slower than a two table join. Of course, I'm biased here, > since my knowledge of the more bizarre db's is limited. I've only seen things > like sybase, oracle, mysql, postgres and mssql.
No - you are *probably* right that the single table query will be faster (less optimization time needed, fewer IOs). However, maintaining the denormalized schema can be a serious issue. In the work that I've done there's nearly *never* any single table queries, because it wouldn't make sense to hit the database multiple times to get the data for the various tables and then join it together later instead of querying all the relevant data in one go (possibly using a temporary table/intermediat storage to create the final result set). My $0.02... Michael -- Michael Peppler Data Migrations, Inc. [EMAIL PROTECTED] *or* [EMAIL PROTECTED] http://www.mbay.net/~mpeppler International Sybase User Group: http://www.isug.com
