How Non-Clustered Index Key Columns Are Stored

Kendra Little walks through page-level details on a non-clustered index:

Just like in the root page and the intermediate pages, the FirstName and RowID columns are present.

Also in the leaf: CharCol, our included column appears! It was not in any of the other levels we inspected, because included columns only exist in the leaf of a nonclustered index.

Kendra does a great job of explaining the topic.

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