How to find disk space used by the SQL Server Database

• Find out database size as a whole and also the data file and log file space usage

EXEC sp_helpdb @dbname= 'StairWay3'

• Find space used by each table

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