通过sql语句查看MYSQL表占空间，数据库所占空间

通过sql语句查看MYSQL表占空间，数据库所占空间
Data_length:表中数据的大小
Index_length:表的索引的大小
Data_free: 表空间的大小
data_Free :如果是共享表空间 data_free 是共享表空间的大小而非数据的大小。 如果是独享表空间才是该表的剩余空间。

1、查看数据库所占空间

SELECT CONCAT(TRUNCATE(SUM(data_length)/1024/1024,2),"MB") AS data_size,
CONCAT(TRUNCATE(SUM(max_data_length)/1024/1024,2),"MB") AS max_data_size,
CONCAT(TRUNCATE(SUM(data_free)/1024/1024,2),"MB") AS data_free,
CONCAT(TRUNCATE(SUM(index_length)/1024/1024,2),"MB") AS index_size
FROM information_schema.tables WHERE TABLE_SCHEMA = "数据库名称";

2、查看表所占空间

SELECT CONCAT(TRUNCATE(SUM(data_length)/1024/1024,2),"MB") AS data_size,
CONCAT(TRUNCATE(SUM(max_data_length)/1024/1024,2),"MB") AS max_data_size,
CONCAT(TRUNCATE(SUM(data_free)/1024/1024,2),"MB") AS data_free,
CONCAT(TRUNCATE(SUM(index_length)/1024/1024,2),"MB") AS index_size
FROM information_schema.tables WHERE TABLE_NAME = "userBase";