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Ideally the query path is determined by the query optimizer. The optimizer will analyze the SQL statement and select the best query path. It normally uses indexes for joins, sorting, groupings as well as filtering. Of course sometimes a query is best executed as sequential scan. Informix identifies the best path through the use of statistics that you or the DBA or somebody updates on a regular basis. If these statistics are not up-to-date, Informix might choose a not-so-optimal query path. If you doubt Informix's optimizer, you can use Informix's optimizer directives to force it to choose a specific path of your choosing. And to determine if it is indeed the "best/fastest" you can use SET EXPLAIN to generate the query path, and look at the cost. More information is provided in the Informix's Performance Guide which is available at Informix's web site. -----Original Message----- From: ASA GSI [mailto:jbruce@asaglobalserv.com] Sent: Wednesday, August 16, 2000 1:43 PM To: informix-list@iiug.org Subject: How Informix determines Index Hi, How does Informix determine the index for an SQL statement if the table has more than one index and how can a programmer try to use the best/fastest index? Thanks again Jordan