View the usage of each mysql database and the last modification time of each table in the database

These two statements are usually used to maintain the mysql database.
 
1. view the size of each database in mysql
 
SELECT sum (DATA_LENGTH) + sum (INDEX_LENGTH) FROM information_schema.tables where TABLE_SCHEMA = 'database _ name ';
The result is in bytes, except 1024 for K and 1048576 for M.
 
 
2. view the last mysql modification time of the table
 
SELECT TABLE_NAME, UPDATE_TIME FROM information_schema.tables where TABLE_SCHEMA = 'database _ name ';
View the last update time of the table in the database. (If it has not been updated for a long time, it does not mean it is not used now ).

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