title: My query doesn't work Postgresql-Python
body: <p>Im having in my database a table with name <strong>sounds</strong>.Table sounds got these columns : </p>
  
  <p><em>Start_Time,End_Time,Salience_Label,Class_Label,Bitrate,Bitdepth,Samplerate</em></p>
  
  <p>I'm using a combobox which values are my column names.I also have an entry where i write some values.I want to query my database (choose something from the combobox and write something in the entry).I get right values from the combobox and from the entry (I print them).
  So i connecto to db with command </p>
  
  <pre><code>conn = psycopg2.connect(conn_string)
  cursor = conn.cursor() //create cursor
  </code></pre>
  
  <p>After this i want to create my query string </p>
  
  <pre><code> SQL = "SELECT * FROM sounds WHERE "+str(app.box.get())+" = '"+str(entry_text)+"'"
  </code></pre>
  
  <p>and then i try to query my db with the command </p>
  
  <pre><code>cursor.execute(SQL)
  rows = cursor.fetchall()
  for row in rows:
       print row
  cursor.close()
  conn.close()
  </code></pre>
  
  <p>i have choose from combobox the value <strong>Bitdepth</strong> and i have writtern in entry the value <strong>1536</strong>.
  But from the cmd i got this message </p>
  
  <p>ProgrammingError: column "bitdepth" does not exist
  LINE 1: SELECT * FROM sounds WHERE Bitdepth = '1536'</p>
  
  <p>I know that this is not the correct way to query my db.Please help,thank you!</p>