Как базы данных, которые не содержат таблиц?
mysql> show tables from test;
Empty set (0.01 sec)
mysql> SELECT S.SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA S
LEFT OUTER JOIN INFORMATION_SCHEMA.TABLES T ON S.SCHEMA_NAME = T.TABLE_SCHEMA
WHERE T.TABLE_SCHEMA IS NULL;
+-------------+
| SCHEMA_NAME |
+-------------+
| test |
+-------------+