如何在 MySQL 中查看表的 auto_increment 值?
若要查看表格的 auto_increment 值,可以使用 SHOW TABLE 命令。
语法如下
SHOW TABLE STATUS LIKE 'yourTableName'\G
语法如下
SELECT `AUTO_INCREMENT` FROM `information_schema`.`TABLES` WHERE `TABLE_SCHEMA` = ‘yourDatabaseName’ AND `TABLE_NAME` =’yourTableName';
为了理解以上语法,我们先创建一个表。创建表的查询如下
mysql> create table viewAutoIncrementDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(20) -> ); Query OK, 0 rows affected (0.59 sec)
现在,你可以使用 insert 命令向表中插入一些记录。查询如下 -
mysql> insert into viewAutoIncrementDemo(UserName) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('Carol'); Query OK, 1 row affected (0.14 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('Bob'); Query OK, 1 row affected (0.08 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('Sam'); Query OK, 1 row affected (0.12 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('Mike'); Query OK, 1 row affected (0.14 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('David'); Query OK, 1 row affected (0.16 sec) mysql> insert into viewAutoIncrementDemo(UserName) values('Larry'); Query OK, 1 row affected (0.11 sec)
使用 select 语句显示表中的所有记录。查询如下 -
mysql> select *from viewAutoIncrementDemo;
以下是输出结果
+--------+----------+ | UserId | UserName | +--------+----------+ | 1 | John | | 2 | Carol | | 3 | Bob | | 4 | Sam | | 5 | Mike | | 6 | David | | 7 | Larry | +--------+----------+ 7 rows in set (0.00 sec)
这里有查看表格 auto_increment 值的查询
mysql> SHOW TABLE STATUS LIKE 'viewAutoIncrementDemo'\G
以下是输出结果
*************************** 1. row *************************** Name: viewautoincrementdemo Engine: InnoDB Version: 10 Row_format: Dynamic Rows: 7 Avg_row_length: 2340 Data_length: 16384 Max_data_length: 0 Index_length: 0 Data_free: 0 Auto_increment: 8 Create_time: 2019-03-02 04:05:20 Update_time: 2019-03-02 04:06:11 Check_time: NULL Collation: utf8_general_ci Checksum: NULL Create_options: Comment: 1 row in set (0.08 sec)
以下是第二个查询
mysql> SELECT `AUTO_INCREMENT` -> FROM `information_schema`.`TABLES` -> WHERE `TABLE_SCHEMA` = 'sample' -> AND `TABLE_NAME` = 'viewAutoIncrementDemo';
以下是输出结果
+----------------+ | AUTO_INCREMENT | +----------------+ | 8 | +----------------+ 1 row in set (0.00 sec)
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