轻松掌握MySQL函数中的last_insert_id()

wing@3306>show create table tt;
+-------+-----------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                           |
+-------+-----------------------------------------------------------------------------------------------------------------------+
| tt | CREATE TABLE `tt` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-----------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
# 没有指定值的时候，last_insert_id()符合预期希望
wing@3306>insert into tt values();
Query OK, 1 row affected (0.00 sec)
wing@3306>select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
|    1 |
+------------------+
1 row in set (0.00 sec)
wing@3306>insert into tt values();
Query OK, 1 row affected (0.00 sec)
wing@3306>select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
|    2 |
+------------------+
1 row in set (0.00 sec)
# what?不是应该是5么，为什么是第一个插入的值3？last_insert_id开始有一点不符合预期了。。
wing@3306>insert into tt values(),(),();
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
wing@3306>select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
|    3 |
+------------------+
1 row in set (0.00 sec)
wing@3306>insert into tt values(),(),();
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
wing@3306>select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
|    6 |
+------------------+
1 row in set (0.00 sec)
# 纳尼？按照预期不是10么？为什么还是之前的6？last_insert_id()我不懂你啊。。
wing@3306>insert into tt values(10);
Query OK, 1 row affected (0.01 sec)
wing@3306>select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
|    6 |
+------------------+
1 row in set (0.00 sec)