1.1 怎样将现有的 MyISAM 数据库转换为 InnoDB:mysql -u [USER_NAME] -p -e "SHOW TABLES IN [DATABASE_NAME];" | tail -n +2 | xargs -I '{}' echo "ALTER TABLE {} ENGINE=InnoDB;" > alter_table.sql perl -p -i -e 's/(search_[a-z_]+ ENGINE=)InnoDB//1MyISAM/g' alter_tabl...
mysql> select concat(round(sum(data_length)/(1024*1024),2) + round(sum(index_length)/(1024*1024),2),'MB') as 'DB Size' -> from tables -> where table_schema='INVOICE'; +---+ | DB Size | +---+ | 7929.58MB | +---+ 1 row in set, 1 warning (0.00 sec) 查看数据所占的...
先手动删除我们创建的data文件夹; 删除Windows服务中的MySql服务,以管理员身份运行CMD,然后执行命令sc delete MySql; 以管理员身份运行CMD并定位到MySql的安装bin目录,然后执行命令mysqld --initialize-insecure,执行完成后会自动创建data文件夹以及对应的所有文件; 然后再执行命令mysqld --install安装MySql服务; 到此,...
To find a string in a certain field and replace it with another string: update [table_name] set [field_name] = replace([field_name],'[string_to_find]','[string_to_replace]');
在bin路径下输入mysqld --initialize-insecure(程序会在data文件夹下创建许多文件) 继续输入mysqld -install(服务已经重新安装了) 开启mysql服务,输入net start mysql MYSQL报错 -- 出现Failed to find valid data directory._Nikita-CSDN博客_failed to find valid data directory. ...
mysql> DROP TABLE table_name; A schema/database can hold many tables. You can imagine a schema as a folder you create on your Operating System.Sometimes, it becomes overwhelming, and you can lose track of the tables you have created in your schema and want to list all the tables in ...
CREATE TABLE testhash ( fname VARCHAR(50) NOT NULL, lname VARCHAR(50) NOT NULL, KEY USING HASH(fname) ) ENGINE=MEMORY; 1. 2. 3. 4. 5. 包含的数据如下: 假设索引使用hash函数f( ),如下: f('Arjen') = 2323 f('Baron') = 7437 ...
当使用findAll语句时遇到问题,可能是由于以下几个方面引起的: 1. 数据库连接问题:首先需要确保数据库连接已经建立并且正常。可以检查数据库连接的配置信息,包括数据库地址、端口号、用户名和密码等...
Table data: Code: SELECT item_code, COUNT( quantity ) x FROM item GROUP BY quantity HAVING x >1 Sample Output: Count duplicate records in MySQL To count the total duplicate (or more) 'quantity' of 'item' table you can use the following query: ...
mysql>show table status\G***1.row***Name:sbtest1Engine:InnoDBVersion:10Row_format:DynamicRows:947263Avg_row_length:241Data_length:228466688Max_data_length:0Index_length:275906560Data_free:26214400Auto_increment:1000001Create_time:2021-04-3014:03:29Update_time:NULLCheck_time:NULLCollation:utf8mb4...