SQL语句的问题，求助！！！

select t.ID,
       t.SCHOOL_NAME,
       (select count(*) from T_STUDENT where SCHOOL_ID = t.ID and ISACTIVE = 1) STUCOUNT,
       (select count(*) from (select distinct STUDENT_ID from T_BUSINESS where SCHOOL_ID = t.ID and (STATUS = 1 or STATUS = 2))) BIZCOUNT
 from (select tb.*, rownum rn from T_SCHOOL tb where ISACTIVE = 1 and rownum <= 20) t
 where rn > 0 order by CITY, REGIONNAME, SCHOOL_NAME;

获取BIZCOUNT的时候里面的t.ID得不到值，有什么办法吗？
[解决办法]

select t.ID,
       t.SCHOOL_NAME,
       (select count(*) from T_STUDENT where SCHOOL_ID = t.ID and ISACTIVE = 1) STUCOUNT,
       (select count(distinct STUDENT_ID) from T_BUSINESS where SCHOOL_ID = t.ID and (STATUS = 1 or STATUS = 2)) BIZCOUNT
 from (select tb.*, rownum rn from T_SCHOOL tb where ISACTIVE = 1 and rownum <= 20) t
 where rn > 0 order by CITY, REGIONNAME, SCHOOL_NAME;