SQL, zapytanie Raport pracowników

Select sum (Romzary.TotalSpaceMB) from
(SELECT
     t.NAME AS TableName,
     s.Name AS SchemaName,
     p.rows AS RowCounts,
     SUM(a.total_pages) * 8 AS TotalSpaceKB,
     CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,
     SUM(a.used_pages) * 8 AS UsedSpaceKB,
     CAST(ROUND(((SUM(a.used_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS UsedSpaceMB,
     (SUM(a.total_pages) – SUM(a.used_pages)) * 8 AS UnusedSpaceKB,
     CAST(ROUND(((SUM(a.total_pages) – SUM(a.used_pages)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UnusedSpaceMB
FROM
     sys.tables t
INNER JOIN     
     sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN
     sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN
     sys.allocation_units a ON p.partition_id = a.container_id
LEFT OUTER JOIN
     sys.schemas s ON t.schema_id = s.schema_id
WHERE
     t.NAME NOT LIKE 'dt%'
     AND t.is_ms_shipped = 0
     AND i.OBJECT_ID > 255
GROUP BY
     t.Name, s.Name, p.Rows
) as Romzary