get-memory-usage-by-database.sql

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;

SELECT	ISNULL(DB_NAME(database_id), 'ResourceDb') AS DatabaseName
		,TRY_CONVERT(INT,(COUNT(row_count) * 8.0 / (1024.0))) AS [Size (MB)]
FROM	sys.dm_os_buffer_descriptors
GROUP BY database_id
ORDER BY DatabaseName;