Summary

In today's lesson, you learned a good deal about writing queries for MySQL.

The central theme was the SELECT query, the principal tool for getting data out of your database in the form of a resultset. You learned how to construct a WHERE clause, and how to include operators and functions within various parts of the query.

You saw how to sort and group the resultset using ORDER BY and GROUP BY, and how to limit the number of rows returned using LIMIT. All this is fundamental to your SQL skillset, as is the application of the DELETE query for deleting data, which uses the WHERE, LIMIT, and ORDER BY clauses just like SELECT does.

You also covered some more advanced topics, such as the HAVING clause for doing last-minute processing on the resultset, applying further conditions to it (similar to WHERE) just before sending it to the user.

You saw how to channel the output of queries into other tables and files, and you studied the principles of full-text searching using MySQL's powerful MATCH...AGAINST syntax. Finally, you had a brief look at subselects and how to collect resultsets together using UNION.