sql - special characters oracle -

See that I put a special character "μ" in my table on the Oracle database:

  Insert in ABBVV (ABBVV, Definition) values ​​('migration', 'microgram (10 grams of one gram, 10-6 grams)'); Include in abbrev (abrev, definition) values ​​('μmole', 'micromole');  

When I select the data that I get:

  SQL & gt; * Select from ABBEV where definition like '% Micro%'; Abrevé Definition -------------------------------------------------- -------------------------------------------------- ------------ Omi other micro organisms ¿μg microgram (10 grams of one gram, 10-6 grams) ¿μmole micromole SQL & gt;  

Why do I get "¿" before "μ" and how to save it in the included statement?

  Oracle Database 11g Enterprise Edition Release 11.1.0.6. 0 For a proper solution, you must set your  NLS_LANG  Environment variable according to your local codepage  
 It looks like:  
  C: \ & gt; CCP Active Code Page: 850C: \ & gt; Set NLS_LANG = .we 8pc 850c: \ & gt; Scllips .. SQL & gt; Include in abbrev (abrev, definition) values ​​('μmole', 'micromole'); 1 row created sql & gt;  
 
 Another solution to use the function  UNISTR : 
 
  ABBVV (ABBREV, definition) values ​​(INIST ('00B5mole') , 'Micromole');