title: MySQL-How to select first duplicate row of corresponding column value
body: <p>I have a table that contains three columns(A,B,C). All columns are of datatype varchar().Here i want to select only those initial rows which is first duplicate value of column A. Like column A has distinct value (1,2,3) so the initial row that has value 1 in column A need to be retrieved.one more thing i don't have a timestamp column in my dataset.</p>
  
  <pre><code>For value 1 in column A, i need to retrieve row that has 1,2,1 value for column (A,B,C)
  For value 2 in column A, i need to retrieve row that has 2,4,1 value for column (A,B,C)
  For value 3 in column A, i need to retrieve row that has 3,1,1 value for column (A,B,C)
  
  A|B|C
  -----  
  1|2|1
  3|1|2
  3|3|1
  2|4|1
  3|1|2
  3|1|4
  1|2|3
  
  Now i want a Output Table as describe below.
  
  A|B|C
  -----
  1|2|1
  3|1|2
  2|4|1
  </code></pre>