Oracle查询语句select * from scott.emp ;1.--dense_rank()分析函数（查找每个部门工资最高前三名员工信息）select * from (select deptno,ename,sal,dense_rank() over(partition by deptno order by sal desc) a from scott.emp) where a<=3 orde..
目录MySQL基本架构Server 层1、连接器2、查询缓存3、分析器4、优化器5、执行器SQL语句举例：SELECT * FROM `test` WHERE `id`=1;当我们输入一条SQL语句，返回一个结果时，那这条语句在 MySQL 内部的执行过程是怎么的呢？MySQL基本架构下面给出的是 ..
SQL查询语句执行顺序如下：(7) SELECT (8) DISTINCT <select_list>(1) FROM <left_table>(3) <join_type> JOIN <right_table>(2) ON <join_condition>(4) WHERE <where_condition>(5) GROUP BY <group_by_list>(6) HAVING <having_condition>(9) OR..
