you are using a function-LOWER, which will not make use of the unique key
index on ksd.
Mysql does not support function based index, hence your query is doing a
FULL TABLE scan and taking more time.
On Tue, Jul 10, 2012 at 4:46 PM, Darek Maciera <darekmaci...@gmail.com>wrote:
> 2012/7/10 Ananda Kumar <anan...@gmail.com>:
> > can u show the explain plan for your query
> >
>
> Thanks, for reply!
>
> Sure:
>
> mysql> EXPLAIN SELECT * FROM books WHERE LOWER(ksd)=LOWER('4204661375');
>
> +----+-------------+-------------------------+------+---------------+------+---------+------+--------+-------------+
> | id | select_type | table | type | possible_keys |
> key | key_len | ref | rows | Extra |
>
> +----+-------------+-------------------------+------+---------------+------+---------+------+--------+-------------+
> | 1 | SIMPLE | books | ALL | NULL |
> NULL | NULL | NULL | 378241 | Using where |
>
> +----+-------------+-------------------------+------+---------------+------+---------+------+--------+-------------+
> 1 row in set (0.00 sec)
>
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