sql和mysql执行顺序,发现内部机制是一样的.最大区别是在别名的引用上. 一.sql执行顺序 (1)from (2)on (3)join (4)where (5)group by(开始使用select中的别名,后面的语句中都可以使用) (6)avg,sum.... (7)having (8)select (9)distinct (10)order by (11)limit 从这个顺序中我们不难发现,所有的 查询语句都是从from开始执行的,在执行过程中,每个步骤都会为下一个步骤生成一个虚拟表…

一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> ORDER BY <o…

http://www.cnblogs.com/linhaifeng/articles/7372774.html 一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by…

本篇导航: SELECT语句关键字的定义顺序 SELECT语句关键字的执行顺序 准备表和数据 准备SQL逻辑查询测试语句 执行顺序分析 一.SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY…

一.SQL语句定义顺序 1 2 3 4 5 6 7 8 9 10 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition>…

阅读目录 一 SELECT语句关键字的定义顺序 二 SELECT语句关键字的执行顺序 三 准备表和数据 四 准备SQL逻辑查询测试语句 五 执行顺序分析 一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition>…

一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> ORDER BY <o…

一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> ORDER BY <o…

python 3 mysql sql逻辑查询语句执行顺序 一 .SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <havin…

一 SELECT语句关键字的定义顺序 SELECT DISTINCT <select_list> FROM <left_table> <join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> ORDER BY <o…