sql,SELECT table_schema AS '数据库名', ,SUM(data_length + index_length) / 1024 / 1024 AS '数据库大小(MB)' ,FROM information_schema.TABLES ,GROUP BY table_schema;,
``SELECT table_schema AS 'Database', SUM(data_length + index_length) / 1024 / 1024 AS 'Size (MB)' FROM information_schema.TABLES GROUP BY table_schema;
这个查询语句会返回每个数据库的名称和对应的大小(以MB为单位)。information_schema.TABLES
是一个系统视图,它包含了关于所有表的信息,通过聚合data_length
(数据长度)和index_length
(索引长度),我们可以得到每个数据库的总大小。
以下是两个与本文相关的问题及解答:
问题1: 如何查询特定数据库的大小?
答案1: 如果你只想查询特定数据库的大小,可以在上述查询中添加一个WHERE子句来指定数据库名称,要查询名为mydatabase
的数据库大小,可以这样写:
SELECT table_schema AS 'Database', SUM(data_length + index_length) / 1024 / 1024 AS 'Size (MB)' FROM information_schema.TABLES WHERE table_schema = 'mydatabase' GROUP BY table_schema;
问题2: 如何将结果按大小排序?
答案2: 如果你想按照数据库大小进行排序,可以在查询末尾添加一个ORDER BY子句,要按照大小降序排列,可以这样写:
SELECT table_schema AS 'Database', SUM(data_length + index_length) / 1024 / 1024 AS 'Size (MB)' FROM information_schema.TABLES GROUP BY table_schema ORDER BY SUM(data_length + index_length) DESC;
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