title: removing first occurrence of a character in DB2
body: <p>I have a column with values as below:</p>
  
  <pre><code>BOOK # ,7,8
  BOOK # ,2
  BOOK # ,13,14
  </code></pre>
  
  <p>I am generating above column with complex xml aggregate function as below:</p>
  
  <pre><code>SELECT 
  CONCAT('BOOK # ',XMLSERIALIZE(XMLAGG(XMLTEXT(CONCAT(',', SUBSTR(TRIM(TEMP.BOOK_NUM),    
  LOCATE('.',TEMP.BOOK_NUM)+1)))) AS VARCHAR(1024 )))
  FROM TEMP 
  GROUP BY BOOK_ID
  </code></pre>
  
  <p>Temp.book_num is of type 123.2, 123.4 in two different rows. So book_id 123 will have two books 2, 4. Thus to extract 2 and 4 out of two rows of same book_id, I had to write above query. </p>
  
  <p>As clear there is an extra ',' comma coming after the words 'BOOK #' which is redundant and unrequired. </p>
  
  <p>I am not able to modify above query to remove it. </p>
  
  <p>Is there any way possible to remove the first occurrence of a character (comma here) from a column value which could be accomodated in the query above ?</p>
  
  <p>My output should be:</p>
  
  <pre><code>BOOK # 7,8
  BOOK # 2
  BOOK # 13,14
  </code></pre>
  
  <p>Thanks for reading!</p>