SQL Server 2012+ Table size list query

SELECT
    t.NAME AS TableName, 
    p.rows AS RowCounts,
    CONVERT(DECIMAL,SUM(a.total_pages)) * 8 / 1024 / 1024 AS TotalSpaceGB,
    SUM(a.used_pages)  * 8 / 1024 / 1024 AS UsedSpaceGB ,
    (SUM(a.total_pages) - SUM(a.used_pages)) * 8 / 1024 / 1024 AS UnusedSpaceGB,
CONVERT(DECIMAL,SUM(a.total_pages))
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.is_ms_shipped = 0
    AND i.OBJECT_ID > 255
GROUP BY
    t.Name, s.Name, p.Rows
ORDER BY
    TotalSpaceGB DESC, t.Name