List the MB of RAM used by each database

ram_usage.sql

SELECT
    MemoryUsage.DatabaseName,
    SUM(MBUsed)
FROM
(
    SELECT DB_NAME(t.dbid) AS DatabaseName, SUM(size_in_bytes/(1024*1024)) AS MBUsed
    FROM sys.dm_exec_cached_plans AS p
    CROSS APPLY sys.dm_exec_sql_text(p.plan_handle) AS t
    WHERE t.dbid < 32767
    GROUP BY t.dbid
    UNION ALL
    SELECT	DB_NAME(database_id),
		    COUNT (*) * 8 / 1024 AS MBUsed
    FROM	sys.dm_os_buffer_descriptors
    GROUP BY	database_id
) AS MemoryUsage
GROUP BY MemoryUsage.DatabaseName
ORDER BY SUM(MBUsed) DESC