Use below query to find the tables in a database based on Size
SELECT O.Name AS [Table],
SUM(A.Total_Pages) AS [Reserved Pages],
SUM(A.Used_Pages) AS [Used Pages],
(SUM(A.Total_Pages) * 8 / 1024) AS [Reserved (MB)],
(SUM(A.Used_Pages) * 8 / 1024) AS [Used (MB)],
SUM(CASE WHEN A.Type <> 1 THEN A.Used_Pages
WHEN P.Index_ID < 2 THEN A.Data_Pages
ELSE 0
END) AS Pages,
SUM(CASE WHEN ( P.Index_ID < 2 )
AND ( A.Type = 1 ) THEN P.Rows
ELSE 0
END) AS [Rows]
FROM Sys.Objects AS O
JOIN Sys.Partitions AS P ON P.Object_ID = O.Object_ID
JOIN Sys.Allocation_Units A ON P.Partition_ID = A.Container_ID
WHERE O.Type = 'U'
GROUP BY O.Name
ORDER BY [Used Pages] DESC
SELECT O.Name AS [Table],
SUM(A.Total_Pages) AS [Reserved Pages],
SUM(A.Used_Pages) AS [Used Pages],
(SUM(A.Total_Pages) * 8 / 1024) AS [Reserved (MB)],
(SUM(A.Used_Pages) * 8 / 1024) AS [Used (MB)],
SUM(CASE WHEN A.Type <> 1 THEN A.Used_Pages
WHEN P.Index_ID < 2 THEN A.Data_Pages
ELSE 0
END) AS Pages,
SUM(CASE WHEN ( P.Index_ID < 2 )
AND ( A.Type = 1 ) THEN P.Rows
ELSE 0
END) AS [Rows]
FROM Sys.Objects AS O
JOIN Sys.Partitions AS P ON P.Object_ID = O.Object_ID
JOIN Sys.Allocation_Units A ON P.Partition_ID = A.Container_ID
WHERE O.Type = 'U'
GROUP BY O.Name
ORDER BY [Used Pages] DESC