title: String Concatnation on a master table column with out duplicates
body: <p>Can any one please help me by providing sql to concat the string column with out duplicates using only SQL which should work on all the dbs. I need the query for record view / psquery in peoplesoft.   </p>
  
  <p>EG: I have master table CheckList (common_id +seq_3c is key )as  </p>
  
  <pre><code>COMMON_ID SEQ_3C CHECKLIST_CD   
  AA0012   2      C     
  AA0012   1  GRAPP   
  AA0014   1  GD  
  AA0014   2  SD  
  </code></pre>
  
  <p>and child table checklist item as   </p>
  
  <pre><code>COMMON_ID SEQ_3C CHECKLIST_SEQ CHKLST_ITEM_CD STATUS_DT  
      AA0012    2       100          ESSAY 12-MAY-13   
      AA0012    2       200          TOEFL 12-MAY-13   
      AA0012    2       300          TRANS 13-MAY-13   
      AA0012    1       100          APFEE 10-MAY-13  
      AA0012    1       200          GRE 12-MAY-13   
      AA0012    1       300          TRANS 12-MAY-13   
      AA0012    1       400          RECLTR 26-JAN-00   
      AA0014    1       100          APFEE 10-MAY-13   
      AA0014    1       200          GRE 12-MAY-13   
      AA0014    2       100          APFEE 12-MAY-13   
      AA0014    2       200          GRE 26-JAN-00
  </code></pre>
  
  <p>I have condition on child table's column status date(eg: 12_May-13 dated rows ) so for those rows i want to get the single show for each common id with concatted values of checklist_cd with out duplicates.</p>
  
  <p>like as </p>
  
  <pre><code>COMMON_ID CHECKLIST_CD
  AA0012 C,GRAPP
  AA0014 GD, SD
  </code></pre>
  
  <p>please suggest / provide sql for record view/psquery in peoplesoft which should be validated on all the dbs in this case. I need only in sql(pl/sql shouldnt be used).
  If It can be done with any no of intermediate sql/ temporary tables thats also fine.</p>
  
  <p>Thanks,<br>
  Shyam</p>