Get Column Length:
SELECT LEN(Name) AS MyLength FROM Tbl_Test






Get Table Wise Column Size:

select DATA_TYPE, CHARACTER_MAXIMUM_LENGTH,
       NUMERIC_PRECISION, DATETIME_PRECISION,
       IS_NULLABLE
from INFORMATION_SCHEMA.COLUMNS where Table_Name='TableName'


Get List Of Tables in DataBase:

SELECT *
FROM sys.Tables

Get List Table Columns: 

SELECT *
FROM sys.Columns