I have this table
+---------------+------------------+------+-----+------------+--------------
--+
| Field | Type | Null | Key | Default | Extra
|
+---------------+------------------+------+-----+------------+--------------
--+
| ID | int(10) unsigned | | PRI | NULL |
auto_increment |
| Nick | varchar(50) | | MUL | |
|
| Sexo | tinyint(1) | | MUL | 0 |
|
| OK | tinyint(1) | | MUL | 0 |
|
| Inicial | char(1) | | MUL | |
|
+---------------+------------------+------+-----+------------+--------------
--+
With this index
| genteirc | 0 | ID_2 | 1 | ID
| A | 22632 | NULL | NULL | |
| genteirc | 1 | ok | 1 | OK
| A | 2 | NULL | NULL | |
| genteirc | 1 | inicial | 1 | Inicial
| A | 22632 | NULL | NULL | |
| genteirc | 1 | sexo | 1 | Sexo
| A | 22632 | NULL | NULL | |
when I run this query
mysql> explain select Nick from mytable where Inicial='P' AND Sexo=1 and
ok=1;
.
+----------+------+-----------------------------------+-------------+-------
--+-------+------+------------+
| table | type | possible_keys | key |
key_len | ref | rows | Extra |
+----------+------+-----------------------------------+-------------+-------
--+-------+------+------------+
| mytable | ref | ok,inicial,sexo | ok | 1 | const | 10 | where
used |
+----------+------+-----------------------------------+-------------+-------
--+-------+------+------------+
only one index is used, why?
ok is 1 or 0
sexo is 1 or 0
but inicial is A, B, C, D, E, F, G.....Z
So it would be better to use Inicial as index bacause should get less
records...
whta's happening?
Thnaks
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