mysql>ALTER TABLE insect DROP id;mysql>ALTER TABLE insect->ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT FIRST,->ADD PRIMARY KEY(id); 设置序列的开始值 一般情况下序列的开始值为 1,但如果你需要指定一个开始值 100,那我们可以通过以下语句来实现: mysql>CREATE TABLE insect->(->id INT UNSIGNED NOT...
In MySQL 5.7 and earlier, modifying an AUTO_INCREMENT column value in the middle of a sequence of INSERT statements could lead to “Duplicate entry” errors. For example, if you performed an UPDATE operation that changed an AUTO_INCREMENT column value to a value larger than the current maximum...
1 row in set (0.00 sec) 方式3 - 查看表状态show table status 该方式提供了当前DB(use db_name;)下每个表的基本信息;可以通过where条件获取到Auto_increment属性的值; 下述提供的结果值,为下一个自增ID的数值。 mysql> show table status where Name='get_max_id'; +---+---+---+---+---+--...
This enables multiple-row inserts to be reproduced correctly on other servers in a replication setup. To start with an AUTO_INCREMENT value other than 1, set that value with CREATE TABLE or ALTER TABLE, like this: mysql> ALTER TABLE tbl AUTO_INCREMENT = 100;...
在MySQL中,每个字段定义都包含附加约束或者修饰符,这些可以用来增加对所输入数据的约束。今天我们来看一下MySQL的字段约束:NULL和NOT NULL修饰符、DEFAULTAUTO_INCREMENT NULL 和 NOT NULL 修饰符: 可以在每个字段后面都加上这NULL 或 NOT NULL 修饰符来指定该字段是否可以为空(NULL),还是说必须填上数据(NOT NULL...
if an old row in thetable has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted. See Section 13.2.5, “INSERT Statement”. REPLACE is a MySQL extensionto the SQL standard. It either inserts or deletes and...
How to Make Existing Column AUTO_INCREMENT in MySQL If you have a table and you want to set an auto-increment to existing column you can execute the following SQL statement: ALTER TABLE user CHANGE COLUMN id id INT AUTO_INCREMENT;
LOCK_AUTO_INC, /* locks the auto-inc counter of a table in an exclusive mode */ LOCK_NONE, /* this is used elsewhere to note consistent read */ LOCK_NUM = LOCK_NONE/* number of lock modes */ }; 2. dict_table_t: innodb表定义 ...
6 rows in set mysql> delete from table1; Query OK, 6 rows affected mysql> select * from table1; Empty set mysql> select auto_increment from information_schema.tables where table_schema = database() and table_name='table1'; +---+ | auto_increment | ...
在MySQL 5.7 版本中,REPLACE INTO 操作在表存在自增主键的情况下,可能会出现表的auto_increment值主从不一致现象,如果在此期间发生主从故障切换,当原来的slave节点变成了新的master节点,由于表的auto_increment值是小于原主库的,当业务继续写入时,就会收到主键冲突的报错提示。