USE database_name;命令。要使用Python脚本访问MySQL，首先需要安装pymysql模块，然后通过pymysql.connect()函数建立连接，再使用cursor.execute()执行SQL语句。SELECT table_schema "Database", ROUND(SUM(data_length + index_length) / 1024 / 1024, 2) "Size (MB)" FROM information_schema.tables GROUP BY table_schema;来查询数据库大小。order by rand()函数来随机选取数据。如果您想根据某个参照字段进行随机选取，可以使用order by rand()结合limit和where子句来实现。，，``sql，select * from table_name where reference_field = 'value' order by rand() limit 1;，`，，这将从表table_name中随机选取一个满足reference_field = 'value'`条件的数据行。SET @a = 'value';或SELECT @a := 'value';为变量a赋值。Powered By Z-BlogPHP 1.7.3