问题
Similar to SHOW TABLES command, do we have any such command to list all databases created so far?
回答1:
This page mentions the command SHOW DATABASES.
From the manual:
SHOW (DATABASES|SCHEMAS) [LIKE identifier_with_wildcards];
SHOW DATABASES lists all of the databases defined in the metastore. The optional LIKE clause allows the list of databases to be filtered using a regular expression. Wildcards in the regular expression can only be '' for any character(s) or '|' for a choice. Examples are 'employees', 'emp', 'emp*|*ees', all of which will match the database named 'employees'.
回答2:
show databases;
The above query will list all the databases available in the hive metastore.
回答3:
For any such queries involving metadata of the objects, you must use the hive metastore deployed on databases such as MySQL or likes of MySQL. You can use the hive database installed on metastore and use the INFORMATION_SCHEMA views/tables for your queries
来源：https://stackoverflow.com/questions/19781965/how-to-list-all-hive-databases-being-in-use-or-created-so-far