I/O Query - Average Stall times per database

Adapted from Glenn Berry's Average Stalls query

SELECT
DB_NAME(database_id) AS [Database Name]
,AVG(CAST(io_stall_read_ms/(1.0 + num_of_reads) AS NUMERIC(10,1))) AS [avg_read_stall_ms]
,AVG(CAST(io_stall_write_ms/(1.0+num_of_writes) AS NUMERIC(10,1))) AS [avg_write_stall_ms]
,AVG(CAST((io_stall_read_ms + io_stall_write_ms)/(1.0 + num_of_reads + num_of_writes) AS NUMERIC(10,1))) AS [avg_io_stall_ms]
FROM sys.dm_io_virtual_file_stats(null,null)
GROUP BY DB_NAME(database_id)
ORDER BY DB_NAME(database_id)

Link : Glenn Berry's Performance Queries