You should fill in the blanks.
select
@myWhereString =stuff((select 'or isnull('+COLUMN_NAME+','''') = '''' ' as [text()]
from Primebet.INFORMATION_SCHEMA.COLUMNS
where TABLE_NAME = 'YourTable'
and (column_name like 'col_as%'
or
column_name like 'col_m%')
for xml path('')),1,3,'')
set @myWhereString ='rest of your query'+ @myWhereString
exec executesql with your query