On Mon, 2006-08-21 at 07:39 +1000, Chris wrote: > Ow Mun Heng wrote: > > On Sun, 2006-08-20 at 19:59 +1000, chris smith wrote: > >> On 8/20/06, Ow Mun Heng <[EMAIL PROTECTED]> wrote: > >>> I'm have a query like so > >>> > >>> select > >>> A, > >>> index_A > >>> from > >>> tableA > >>> join tableB > >>> on tableB.indexA = tableA.indexA > >>> > >>> > >>> select > >>> A, > >>> index_A > >>> from > >>> tableA > >>> join tableB > >>> on tableB.A = tableA.A > >>> > >>> whcih would be more efficient? using the where clause which uses the > >>> index or the one which isn't index? > >> If you join using the field that is indexed, this will use an index. > >> > >> If you join using the field that isn't indexed, it can't use an index. > > > > I take it that that means yes, it's more efficient performance wise to > > always use an index. > > Of course, same as any query ;)
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