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Re: Improving count(distinct) - group by - query
Posted by: KimSeong Loh
Date: February 18, 2005 02:54AM

The query needs to read all the 5 million records.

Maybe a composite index on (tel,telefb) can help a little bit. This allows the index to be used to do the count, so no need to read the data rows.

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Re: Improving count(distinct) - group by - query
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February 18, 2005 02:54AM


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