MySQL - MySQL如何优化LEFT JOIN和RIGHT JOIN

[MySQL如何优化LEFT JOIN和RIGHT JOIN文档]

http://dev.mysql.com/doc/refman/5.1/zh/optimization.html#left-join-optimization

[MySQL网站]

http://www.mysql.com/

[MySQL相关论坛]

http://database.board.newsmth.net/, 不针对MySQL

[MySQL语法]

CREATE TABLE, http://dev.mysql.com/doc/refman/5.1/zh/sql-syntax.html#create-table

SHOW TABLE STATUS, http://dev.mysql.com/doc/refman/5.1/zh/sql-syntax.html#show-table-status

日期和时间类型概述文档, http://dev.mysql.com/doc/refman/5.1/zh/column-types.html#date-and-time-type-overview

JOIN语法文档, http://dev.mysql.com/doc/refman/5.1/zh/sql-syntax.html#join

DATEDIFF(expr1,expr2)语法文档, http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_datediff

MySQL如何优化LEFT JOIN和RIGHT JOIN文档, http://dev.mysql.com/doc/refman/5.1/zh/optimization.html#left-join-optimization