常见select查询总结 周万春 查看单个数据库数据大小 [root@db01 ~]# mysql.dba -e "select table_name,concat(round((data_length + index_length + data_free)/1024/1024,2),'MB') from information_schema.tables where table_schema='world';" +-----------------+--------------------------------------------------------------------------+ | table_name | concat(round((data_length + index_length + data_free)/1024/1024,2),'MB') | +-----------------+--------------------------------------------------------------------------+ | city | 0.52MB | | country | 0.09MB | | countrylanguage | 0.16MB | +-----------------+--------------------------------------------------------------------------+ 查看单张表数据大小 [root@db01 ~]# mysql.dba -e "select table_name,concat(round((data_length + index_length + data_free)/1024/1024,2),'MB') from information_schema.tables where table_schema='world' and table_name='city';" +------------+--------------------------------------------------------------------------+ | table_name | concat(round((data_length + index_length + data_free)/1024/1024,2),'MB') | +------------+--------------------------------------------------------------------------+ | city | 0.52MB | +------------+--------------------------------------------------------------------------+ 查看所有数据库的大小 [root@db01 ~]# mysql.dba -e "select table_schema,concat(round(sum((data_length + index_length + data_free)/1024/1024),2),'MB') as data_size from information_schema.tables group by table_schema;" +--------------------+-----------+ | table_schema | data_size | +--------------------+-----------+ | app01 | 0.02MB | | information_schema | 80.16MB | | mysql | 6.51MB | | performance_schema | 0.00MB | | sakila | 14.45MB | | student | 0.06MB | | sys | 0.02MB | | world | 0.77MB | +--------------------+-----------+