Re: WHERE IN vs. WHERE OR OR OR

Daniel Kirkdorffer wrote: > > Hi, > > Using JDBC against and Informix database I was wondering if anyone > knew which WHERE clause would be more efficient: > > SELECT x FROM y WHERE x IN (1, 2, 3,..., n)> > or > > SELECT x FROM y WHERE x = 1 OR x = 2 OR x = 3 OR ... OR x = n> > (Where x is a primary key) > > Would the choice be the same if n > 100, or even n > 1000? > > Any suggestions would be greatly appreciated. In general an IN clause is more efficient than a set of OR conditions. The kicker is that if the table is fragmented, and in a few other esotheric circumstances the optimizer will expand either into a set of UNIONs. Art S. Kagel