On Mon, Sep 12, 2005 at 09:43:57AM -0400, Reid Thompson wrote: > Example: > assume a table of 10 columns, three of which are fname, lname, and dob. > If an index is created on (fname, lname, dob), will a query that > utilizes two of the columns ( select 'data' from table where fname = 'X' > and lname = 'Y') utilize the index? Yes, if it is selective enough. (It _can_ use the index, which does not mean that it _will_ use it.) Note that if your example query used the columns (lname, dob), the answer would be "no." -- Alvaro Herrera -- Valdivia, Chile Architect, www.EnterpriseDB.com Officer Krupke, what are we to do? Gee, officer Krupke, Krup you! (West Side Story, "Gee, Officer Krupke") ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
