sql - Finding Rows based on a set of same columns in ORACLE -

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consider following table:-

-----------------------------------------   id      teacher    subject     grade -----------------------------------------   1        jack       physics      8   2        paul       chemistry    10   3        susan      english      6   4        jack       maths        8   5        jack       physics     10   6        paul       chemistry   10

i want identify rows same values teacher , subject columns. irrespective of values in id , grade columns. following rows identified:-

 -------------------------------------   id      teacher     subject   grade  -------------------------------------   1        jack       physics      8   2        paul       chemistry    10   5        jack       physics     10   6        paul       chemistry   10  -------------------------------------

how achieve such result in oracle sql.

select * table1 t1 exists (   select null table1 t2   t1."teacher" = t2."teacher"     , t1."subject" = t2."subject"     , t1."id" <> t2."id" ) order "id"

demo: http://sqlfiddle.com/#!4/3d2bd4/3


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