RE: [PHP] counting number of records in a MySQL table; how do I get

[snip] > I agree that COUNT is an optimized return, but for a situation where you > are > retrieving data from the query for whatever use it is more efficient to > use > mysql_num_rows() to return the count of this particular query than it > would > be to issue a second query, no? Yes, it all depends on what you are doing with the results. If you are selecting everything, and using everything in your page, then, yeah, use mysql_num_rows. A second query of the same thing just for COUNT(*) would be inefficient. > I guess we could get into some semantical discussion at this point about > efficiency. I am an old school coder, and as such I have been taught to > conserve CPU cycles and round trips to other servers. As technology grows > some of these things could go by the wayside because processing power has > increased multi-fold since I began my foray many years ago. I always seek > to > send the fewest queries to the database server where possible... efficient > query design, use of other functions available in the programming language > to provide additional data, or any number of other tricks, tips, and magic > tricks have helped to keep things clean. > > So, is mysql_num_rows() less efficient than a second query asking SELECT > COUNT(*)? Is there any way to time the two where doing a query like the > above example? The two query method is efficient when you have large tables and you are only going to use a subset of the results. Like in showing X records out of Y. I could do a little benchmarking script to see what kind of time differences we are talking about. Maybe it's so minor that it doesn't matter... I think we're arguing with each other even though we agree on everything. :) ---John Holmes...