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Editorial Team
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Asked: 2026-06-01T16:12:47+00:00

I have a table from which I need to obtain rows ordered by a

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I have a table from which I need to obtain rows ordered by a field in descending order. When running an EXPLAIN query like the following:

EXPLAIN SELECT ... FROM table WHERE ... ORDER BY field DESC

I get Using where; Using filesort in the Extra column. So I try to create a DESC index:

CREATE INDEX name ON table (field DESC);

But when I run EXPLAIN again, I get the same Using where; Using filesort in the Extra column and the performance is pretty much the same.

What am I doing wrong?

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1 Answer

  1. Editorial Team

    That’s one of those MySQL “features” where it silently ignores your request to do something because it’s simply not implemented:

    From http://dev.mysql.com/doc/refman/5.5/en/create-index.html

    “An index_col_name specification can end with ASC or DESC. These keywords are permitted for future extensions for specifying ascending or descending index value storage. Currently, they are parsed but ignored; index values are always stored in ascending order“

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