title: SQL - Add up column value singletable
body: <p>I have a table Like This</p>
  
  <pre><code>Id|purchase_date | Purchase_price
  1 |02-May-17     |$10.00
  2 |02-May-17     |$20.00
  3 |02-May-17     |$30.00
  </code></pre>
  
  <p>I want to write a query where the  sum of all purchase_price will calculated on the basis of purchase_date.
  Can Someone Please suggest the query? </p>