How to prepare Alter Statment for All Table Columns

SELECT 'Alter table  '+QUOTENAME(SCHEMA_NAME(tb.[schema_id])) +'.'+ QUOTENAME(OBJECT_NAME(tb.[OBJECT_ID])) +
'  alter  column '+ C.NAME +'  '+T.name+' ('+convert(varchar(100),C.max_length)+')'+' '+case when c.is_nullable=0
then '  not null' else ' null' end FROM SYS.COLUMNS C INNER JOIN SYS.TABLES tb ON tb.[object_id] = C.[object_id]
   INNER JOIN SYS.TYPES T ON C.system_type_id = T.user_type_id
WHERE tb.[is_ms_shipped] = 0  and T.name like '%decimal%'
ORDER BY tb.[Name]