Help regarding query

Question

I have 2 tables student and student_subject
TABLE: STUDENT
STUDENT_SEQ|ID
1|I1
2|I2
3|I3
4|I4TABLE: SUB_CLASS
SUB_CLASS|STUDENT_SEQ
SUB1|1
SUB2|1
SUB3|2
SUB1|3
SUB3|4I want to retreive only STUDENTS who have been enrolled to both SUB1 and SUB2.
Edited by: vamsikrishnagorantla on Dec 27, 2010 4:08 PM

Answer 1

with t1 as (
            select 1 student_seq,'I1' id from dual union all
            select 2,'I2' from dual union all
            select 3,'I3' from dual union all
            select 4,'I4' from dual
     t2 as (
            select 'SUB1' sub_class,1 student_seq from dual union all
            select 'SUB2',1 from dual union all
            select 'SUB3',2 from dual union all
            select 'SUB1',3 from dual union all
            select 'SUB3',4 from dual
select  t1.student_seq,
        id
  from  t1
  where 2 = (
             select  count(distinct sub_class)
               from  t2
               where sub_class in (
                                   'SUB1',
                                   'SUB2'
                 and t2.student_seq = t1.student_seq
STUDENT_SEQ ID
          1 I1
SQL> SY.