Indexing

Indexes: When Column Selectivity Is Not Always A Requirement

  • Article

While preparing for my SQL Saturday Salt Lake City presentation, Climbing the B-Tree, I ran into one of the “word of mouth” facts that the first column of an index should be highly selective, i.e., it should only point to one or a few rows. This is not always the case and I’ll show you […]

5 (1)

2020-09-16

2,188 reads

“Included columns” for non-clustered indexes explained

  • Article

Microsoft SQL Server has the feature to use “Included columns” for the creation of non-clustered indexes. This feature and its benefits and disadvantages will be explained in the following article. Included columns can be used to create a covering indexes without including all the data into the key columns. This covering index has the advantage […]

4.17 (6)

2019-09-17

7,481 reads

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