MySQL "WITH" clause

Update: MySQL 8.0 is finally getting the feature of common table expressions, including recursive CTEs.

Here's a blog announcing it: http://mysqlserverteam.com/mysql-8-0-labs-recursive-common-table-expressions-in-mysql-ctes/

Below is my earlier answer, which I originally wrote in 2008.

MySQL 5.x does not support queries using the WITH syntax defined in SQL-99, also called Common Table Expressions.

This has been a feature request for MySQL since January 2006: http://bugs.mysql.com/bug.php?id=16244

Other RDBMS products that support common table expressions:

• Oracle 9i release 2 and later:
  http://www.oracle-base.com/articles/misc/with-clause.php
• Microsoft SQL Server 2005 and later:
  http://msdn.microsoft.com/en-us/library/ms190766(v=sql.90).aspx
• IBM DB2 UDB 8 and later:
  http://publib.boulder.ibm.com/infocenter/db2luw/v8/index.jsp?topic=/com.ibm.db2.udb.doc/admin/r0000879.htm
• PostgreSQL 8.4 and later:
  https://www.postgresql.org/docs/current/static/queries-with.html
• Sybase 11 and later:
  http://dcx.sybase.com/1100/en/dbusage_en11/commontblexpr-s-5414852.html
• SQLite 3.8.3 and later:
  http://sqlite.org/lang_with.html
• HSQLDB:
  http://hsqldb.org/doc/guide/dataaccess-chapt.html#dac_with_clause
• Firebird 2.1 and later (the first Open Source DBMS to support recursive queries):http://www.firebirdsql.org/file/documentation/release_notes/html/rlsnotes210.html#rnfb210-cte
• H2 Database (but only recursive):
  http://www.h2database.com/html/advanced.html#recursive_queries
• Informix 14.10 and later:https://www.ibm.com/support/knowledgecenter/SSGU8G_14.1.0/com.ibm.sqls.doc/ids_sqs_with.htm

You might be interested in somethinkg like this:

select * from (    select * from table) as Subquery

You've got the syntax right:

WITH AuthorRating(AuthorName, AuthorRating) AS   SELECT aname         AS AuthorName,          AVG(quantity) AS AuthorRating   FROM Book   GROUP By Book.aname

However, as others have mentioned, MySQL does not support this command. WITH was added in SQL:1999; the newest version of the SQL standard is SQL:2008. You can find some more information about databases that support SQL:1999's various features on Wikipedia.

MySQL has traditionally lagged a bit in support for the SQL standard, whereas commercial databases like Oracle, SQL Server (recently), and DB2 have followed them a bit more closely. PostgreSQL is typically pretty standards compliant as well.

You may want to look at MySQL's roadmap; I'm not completely sure when this feature might be supported, but it's great for creating readable roll-up queries.