Check database total size in use :-

SELECT DB_NAME(database_id) AS DatabaseName,
       Name AS Logical_Name,
       Physical_Name,
       (size * 8) / 1024 SizeMB
FROM sys.master_files
WHERE DB_NAME(database_id) = 'YOUR_DB'

Check two table where columns are not matching :-

select column_name from INFORMATION_SCHEMA.COLUMNS 
where TABLE_NAME='Table_name1'
except
select column_name from INFORMATION_SCHEMA.COLUMNS 
where TABLE_NAME='Table_name2'