Question

I’m selecting Data from a mysql database table.
When i’m searching a specific date, my index is wiorking fine.
When I’m searching data between two dates the index isn’t working and the query takes to long.
Has anybody an idea how can i improve the query or the index?

Query A:

EXPLAIN SELECT * FROM sal_import  
WHERE dateStats>="2011-07-28" AND dateStats<="2011-07-30" GROUP BY f_shop


id  select_type table   type    possible_keys   key key_len ref rows    Extra
1   SIMPLE  i   range   dateStats   dateStats   3   (NULL)  7896    Using where; Using temporary; Using filesort

Query B:

EXPLAIN SELECT * FROM sal_import i 
WHERE dateStats="2011-07-30" GROUP BY f_shop


id  select_type table   type    possible_keys   key key_len ref rows    Extra
1   SIMPLE  i   ref dateStats   dateStats   3   const   2182    Using where

This is the index of the table:

ALTER TABLE sal_import ADD INDEX(dateStats,f_shop);

Thank you very much.

Answer 1

Try this:

SELECT * FROM sal_import WHERE dateStats BETWEEN '2011-07-28' AND '2011-07-30'

Also see http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html