proc sql;
create table teen as
select name as fname,age
from sashelp.class
where age>12;
quit;

*第一种方法;
proc sql; select * from (select age,count(age) as many        from teen       group by age) having many=max(many);quit;

*第二种方法;
proc sql; select age,count(age) as many from teen group by age having many=max(many);quit;

*SAS 报错 ERROR: 不支持以此种方式嵌套的汇总函数。;

请问各位大侠SASsql 嵌套的具体过程是怎么样的哦，什么时候是合法的，什么时候不能执行？谢谢的啦