MySQL LAST_INSERT_ID() 函数有什么用？

mysql> Create table Student(Id INT PRIMARY KEY NOT NULL AUTO_INCREMENT, Name Varchar(5));
Query OK, 0 rows affected (0.13 sec)

mysql> Insert into student(Name) Values('Raman');
Query OK, 1 row affected (0.06 sec)

mysql> Insert into student(Name) Values('Rahul');
Query OK, 1 row affected (0.07 sec)

mysql> Select* from student;
+----+-------+
| Id | Name |
+----+-------+
| 1 | Raman |
| 2 | Rahul |
+---+-------+
2 rows in set (0.00 sec)

mysql> Select Last_insert_id();
+------------------+
| Last_insert_id() |
+------------------+
|                2 |
+------------------+
1 row in set (0.00 sec)