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jschell19-Jan-24 4:52
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"index is sorted on col1, then col2. Meaning, col1 will be located first, then most rows following with the same col1 will be sorted on col2."

(My quote button still not working.)

Re-read that response after looking at post to other response.

That phrasing is a misstatement about how it works.

A table storage in a database is quite complicated. Often, but not always, records (rows) are inserted at the end of the table. Doesn't matter whether indexes exist or not. The reason for doing it that way is because it is faster.

There are some implementation details about how that works technically but 'at the end' is the best technical description. Clustered indexes do this differently but not specifically in terms of sorting anything.

After the insert the index(es) are updated. That involves storing some of the data from the row (columns in the index) and a pointer to the row itself.

Sorting is not something that is related to the table nor even to indexes. In SQL you can specifically ask for a specific sort order. If you do not do that then how the records (rows) are returned is somewhat random. And that becomes even more true when things like joins are factored in.

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