title: Converting symbols from outside of alphabet caused by copying text in different encoding
body: <p>In my database I should only have data written using Polish alphabet but sometimes there are symbols not included in Polish alphabet (words copied from source with different encoding) that correspond to Polish letters in another encoding. Is it possible to somehow convert symbols outside of Polish alphabet to corresponding letters?
  The only solution I figured is to manually find and replace those characters but maybe you have better solution to my problem.</p>
  
  <p>Question concerns Oracle SQL Language.</p>
  
  <p>I don't have database in front of me but as I remember correctly the example could look like this - two rows from my db:</p>
  
  <p>ŚWIAT</p>
  
  <p>ÚWIAT</p>
  
  <p>and what I need is to convert Ú that doesn't belong to Polish alphabet to Ś.</p>