At 5:40 PM +0000 02-02-2000, James Gray wrote:
>You can't use an index if you have an OR!!!
>Please tell me I've miss-understood this, can I work around it???
Break your query into two separate queries so that you don't have an
OR in it.
>
>-----Original Message-----
>From: sasha@stripped [mailto:sasha@stripped]On
>Behalf Of sasha@stripped
>Sent: 02 February 2000 16:33
>To: james.gray@stripped
>Cc: mysql@stripped
>Subject: Re: Explain type 'ALL'.
>
>
>James Gray wrote:
>>
>> I am looking at the result of an "explain select" that does *not* perform
>a
>> join,
>> I'm getting a 'ALL' in 'type' - the documentation describes this as very
>bad
>> but I'm not performing a join, is this still very bad?
>>
>> Thanks:
>>
>> SQL-query:
>> EXPLAIN SELECT
>BOK_ISBN,BOK_AUTHOR,BOK_TITLE,BOK_PUB,BOK_DATPUB,BOK_BINCODE
>> FROM BOOKS WHERE BOK_AUTHOR LIKE 'bond%' AND BOK_AVAIL='ip' || BOK_TITLE
>> LIKE 'bond%' AND BOK_AVAIL='ip';
>>
>> table type possible_keys key key_len ref
>rows Extra
>> BOOKS ALL BOK_TITLE,BOK_AUTHOR
>1041289 where used
>
>The problems is that MySQL optimizer cannot yet use an index if you have an
>OR.
>
>--
>Sasha Pachev
>
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