ASC=正序(默认值) DESC=倒序
红=三大语句,黄+红=四大语句,蓝+黄+红=五大语句
- 数据操纵语言(DML): SELECT(查询)INSERT(插入) UPDATE(更新) DELETE(删除)
- 数据定义语言(DDL):CREATE(创建数据库或表或索引)ALTER(修改表或者数据库)DROP(删除表或索引)
- 数据控制语言(DCL):GRANT(赋予用户权限) REVOKE(收回权限) DENY(禁止权限)
- 数据查询语言(DQL):是由SELECT子句,FROM子句,WHERE子句组成的查询块
- 事务控制语言(TCL):SAVEPOINT (设置保存点)ROLLBACK (回滚) COMMIT(提交)
执行顺序 | 命令语句 |
---|---|
1 | FROM <left_table> |
2 | ON <join_condition> |
3 | <join_type> JOIN <right_table> |
4 | WHERE <where_condition> |
5 | GROUP BY <grout_by_list> |
6 | WITH {CUTE|ROLLUP} |
7 | HAVING <having_condition> |
8 | SELECT |
9 | DISTINCT <select_list> |
10 | ORDER BY <order_by_list> |
11 | LIMIT <limit_number> |
从1至11,优先级逐渐减小
写法顺序 | 命令语句 |
---|---|
8 | SELECT |
9 | DISTINCT <select_list> |
1 | FROM <left_table> |
3 | <join_type> JOIN <right_table> |
2 | ON <join_condition> |
4 | WHERE <where_condition> |
5 | GROUP BY <grout_by_list> |
6 | WITH {CUTE|ROLLUP} |
7 | HAVING <having_condition> |
10 | ORDER BY <order_by_list> |
11 | LIMIT <limit_number> |
从上至下,传统语法的写法顺序以此从左到右