请问sql 专家一个检索语句的问题

declare @sql varchar(4000);
set @sql='select '+@n1+' count(*) from windbreaker where name like '''%'+@w1+'%''';
exec @sql;
set @sql='select '+@n2+' count(*) from windbreaker where name like '''%'+@w1+'%''';
exec @sql;
set @sql='select '+@n3+' count(*) from windbreaker where name like '''%'+@w1+'%'+@w2+'%'
'';
exec @sql;
set @sql='select '+@n4+' count(*) from windbreaker where name like '''%'+@w2+'%'+@w2+'%'
'';
exec @sql;