MySQL关键字执行顺序

1)Mysql语法顺序，即当sql中存在下面的关键字时，它们要保持这样的顺序：

select[distinct]
from
join（如left join）
on
where
group by
having
union
order by
limit

2)Mysql执行顺序，即在执行时sql按照下面的顺序进行执行：

from
on
join
where
group by
having
select
distinct
union
order by