title: pd.read_sql_query single / double quotes formatting
body: <p>I'm using Python(Jupyter Notebook) and Postgres Database and am struggling to populate a Pandas dataframe.</p>
  
  <p>The sql code runs fine using the query builder in pgAdmin4 which is</p>
  
  <pre><code>SELECT "Date","Close" FROM test WHERE "Symbol" = 'AA'
  </code></pre>
  
  <p>However I can't get this to work in my Jupyter notebook, I assume its something to do with single quotes and double quotes but can't figure out what to change and have hit a wall. In the notebook I'm trying</p>
  
  <pre><code>df = pd.read_sql_query('SELECT "Date","Close" FROM public.test WHERE "Symbol" = AA', conn)
  </code></pre>
  
  <p>but don't know what quotes to use around the AA (data) part of the query, if I use double quotes pandas thinks AA is a column and if I use single quotes it breaks the string.</p>
  
  <p>I'd really appreciate it if someone could point me in the right direction.</p>
  
  <p>Thanks</p>