title: How to change number(7,2) to varchar in oracle?
body: <p>I'm using Oracle 10g. I want to append # to all values in 'sal' column. To acomplish this first I'm trying to change  data type of 'sal' column from numeric to varchar but getting following error 
  <img src="https://i.stack.imgur.com/EPgHL.png" alt="enter image description here"></p>
  
  <p>What am I doing wrong ?</p>