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Table Scan

Nov 24 2008   1:00PM GMT

Back To Basics: What’s the difference between a Scan and a Seek?



Posted by: mrdenny
SQL Server, Back To Basics, Index Performance, Index Scan, Index Seek, Table Scan

There are a few basic operations which SQL will perform when looking for the data that you need.  Here they are listed in the order of worst to best.

  • Table Scan
  • Clustered Index Scan
  • Index Scan
  • Clustered Index Seek
  • Index Seek

The basic rule to follow is Scans are bad, Seeks are good.

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