Get a list databases and their size in MB.

SELECT
  table_schema AS 'Db Name',
  Round(Sum(data_length + index_length) / 1024 / 1024, 3) AS 'Db Size (MB)',
  Round(Sum(data_free) / 1024 / 1024, 3) AS 'Free Space (MB)'
FROM
  information_schema. TABLES
GROUP BY
  table_schema;