space used in all Databases and in all tables in a database

;WITH DataBase_Size (SqlServerInstance,DatabaseName,DatabaseSize,LogSize,TotalSize)
AS
-- Define the CTE query.
(
  SELECT      @@SERVERNAME SqlServerInstance,
            db.name AS DatabaseName,
            SUM(CASE WHEN af.groupid = 0 THEN 0 ELSE af.size / 128.0E END) AS DatabaseSize,
            SUM(CASE WHEN af.groupid = 0 THEN af.size / 128.0E ELSE 0 END) AS LogSize,
            SUM(af.size / 128.0E) AS TotalSize
FROM        master..sysdatabases AS db
INNER JOIN  master..sysaltfiles AS af ON af.[dbid] = db.[dbid]
WHERE       db.name NOT IN ('distribution', 'Resource', 'master', 'tempdb', 'model', 'msdb') -- System databases
            AND db.name NOT IN ('Northwind', 'pubs', 'AdventureWorks', 'AdventureWorksDW')   -- Sample databases
GROUP BY    db.name
)
-- Define the outer query referencing the  name.
SELECT *
FROM DataBase_Size order by TotalSize desc


**************************************

SELECT 
    t.NAME AS TableName,
    s.Name AS SchemaName,
    p.rows AS RowCounts,
    SUM(a.total_pages) * 8 AS TotalSpaceKB, 
    SUM(a.used_pages) * 8 AS UsedSpaceKB, 
    (SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB
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
ORDER BY 
    t.Name

**************************************************
sp_msforeachtable 'exec sp_spaceused [?]'