On 21 Nov 2002, at 15:18, Hans Zaunere wrote:
> Because it seems ineffncient to me, as MySQL must be doing more work to
> calculate the range. Even EXPLAIN tells me this, by showing that a
> less-than-optimal TYPE is being used. Although "WHERE thecolumn =
> '2002-11-17'" doesn't yield any results, EXPLAIN shows that it's using a
> better index type.
Yes, EXPLAIN says that the type is 'range' rather than 'ref', but
you're doing a range query. That's the best you can get for your
query, so there's no point in worrying about what might be optimal
for a different sort of query. The light for searching might be
optimal under the lamppost rather than in the alley, but if you
dropped your keys in the alley you have to search for them there.
If you never care about the time portion of the column, then it would
be better to make it a DATE column, but as long as it's a DATETIME
column then you are looking for a range of values, so 'range' is the
best you're going to get in the EXPLAIN output.
Keith C. Ivey <keith@stripped>
Tobacco Documents Online