Re: utility of an index

2011-08-31 Thread Johan De Meersman
- Original Message - > From: "Dave Dyer" > > It depends on if you want the forest or the trees. A frequently > executed query asks for just the robots. An index is an efficient way to > select 6 of 20,000. As for why the rest are null, null is just a a > random everything else value, l

Re: utility of an index

2011-08-30 Thread Dave Dyer
At 12:43 AM 8/30/2011, mysql-plain-digest-h...@lists.mysql.com wrote: >Not useful to add an index for that. I also wonder why the value is null >(meaning: unknown, not certain) for almost all records. It depends on if you want the forest or the trees. A frequently executed query asks for just t