by Markus Winand.

MySQL Example Scripts for “Partial Results”


This section contains the create and insert statements to run the examples from Chapter 7, “Partial Results in a MySQL database.

Querying Top-N Rows

An indexed Top-N query doesn't show a “filesort” operation in the Extras column:

SELECT *
  FROM sales
 ORDER BY sale_date DESC
 LIMIT 10

+----+-------+-------+-------------+--------+-------+
| id | table | type  | key         | rows   | Extra |
+----+-------+-------+-------------+--------+-------+
|  1 | sales | index | sales_dt_pr | 836092 |       | 
+----+-------+-------+-------------+--------+-------+

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Markus Winand teaches efficient SQL—inhouse and online. He minimizes the development time using modern SQL and optimizes the runtime with smart indexing. His book entitled SQL Performance Explained has become standard reading.

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