title: Finding Rows based on a set of same columns in ORACLE
body: <p>Consider following table:-</p>
  
  <pre><code>-----------------------------------------
    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
  </code></pre>
  
  <hr>
  
  <p>i want to identify the rows with same values for TEACHER and SUBJECT columns. irrespective of values in ID and GRADE columns. The following rows thus will be identified:-</p>
  
  <pre><code> -------------------------------------
    ID      TEACHER     SUBJECT   GRADE
   -------------------------------------
    1        Jack       Physics      8
    2        Paul       Chemistry    10
    5        Jack       Physics     10
    6        Paul       Chemistry   10
   -------------------------------------
  </code></pre>
  
  <p>how to achieve such a result in oracle sql.</p>