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how-to-avoid-table-scan

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User Comments
  Posted by Becky D on February 28, 2011
We ran into a condition where we were trying to join on 2 varchar fields that used a different collation. One field was utf-8 and the other was latin1. This was causing a full table scan on a join between the 2 tables. Once we converted the fields to all be utf-8, query went from 9 seconds down to 0.
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