SQL Listing Databases.

In MySQL you can use the SHOW statement.

SHOW {DATABASES | SCHEMAS}  [LIKE 'pattern' | WHERE expr]

SHOW DATABASES LIKE 'f%'

This will list all the databases which have a name that start with a 'f' character.
You can accomplish the same thing with using a where statement.

SHOW DATABASES WHERE `database` LIKE 'f%'

Observe the special single quotes around the database column.

In SQL server you can select name from master.dbo.sysdatabases.

SELECT name FROM master.dbo.sysdatabases
WHERE name LIKE 'C%'

This will list all the databases which have a name that start with a 'C' character.

In SQL server you can select datname from pg_database.

SELECT datname FROM pg_database
WHERE datname LIKE 'C%'

This will list all the databases which have a datname that start with a 'C' character.

A database in Oracle is something completely different than e.g. in SQL Server, PostgrSQL or MySQL.
Each database is (more or less) a different Oracle installation.
To show the database name you must login with the DBA privilege as user SYSTEM for instance.

SELECT NAME FROM v$database