sql执行顺序
- from
- join
- on
- where
- group by(开始使用select中的别名,后面的语句中都可以使用)
- avg,sum….
- having
- select
- distinct
- order by
参考资料
http://blog.csdn.net/u014044812/article/details/51004754
http://blog.csdn.net/bitcarmanlee/article/details/51004767 (含流程图)
http://blog.csdn.net/u014044812/article/details/51004754
http://blog.csdn.net/bitcarmanlee/article/details/51004767 (含流程图)