Retrieve the sizes of all tables in a schema

gistfile1.sql

SELECT 
  TABLE_NAME, table_rows, data_length, index_length,  
  round(((data_length + index_length) / 1024 / 1024),2) 'Size in MB' 
FROM information_schema.TABLES 
WHERE table_schema = 'YOUR_DB_NAME' and TABLE_TYPE='BASE TABLE' 
ORDER BY data_length DESC
;