1:显示数据库版本信息:
SELECT @@version;
2:显示数据库实例信息:
SHOW VARIABLES LIKE "%version%";
3:显示数据库表空间使用情况:
SELECT table_schema AS "Database", SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)" FROM information_schema.tables GROUP BY table_schema;
4:显示数据库连接信息:
SHOW PROCESSLIST;
5:显示数据库查询缓存命中率:
SHOW STATUS LIKE 'Qcache_hits';
6:显示数据库锁信息:
SHOW OPEN TABLES WHERE In_use > 0;
7:显示数据库慢查询:
SELECT * FROM mysql.slow_log;
8:显示数据库索引统计信息:
SHOW INDEX FROM table_name;
9:显示数据库存储过程和函数:
SHOW PROCEDURE STATUS;
SHOW FUNCTION STATUS;
10:显示数据库备份和恢复脚本:
# 备份数据库
mysqldump -u username -p database_name > backup.sql
# 还原数据库
mysql -u username -p database_name < backup.sql
11:查询数据库用户列表
SELECT User, Host FROM mysql.user;
12:创建新用户并授权
CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON database_name.* TO 'newuser'@'localhost';
FLUSH PRIVILEGES;
13:修改用户密码
ALTER USER 'username'@'host' IDENTIFIED BY 'new_password';
FLUSH PRIVILEGES;
14:优化表
OPTIMIZE TABLE table_name;
15:查看数据库状态
SHOW STATUS;