title: How to convert date(string type) into date(date time ) in oracle
body: <p>I am stuck with a Oracle query. In my dashboard app, we have to show a summary graph for total of details lines basically. In one particular tab,  we need the datetime in the details, but we group on the summary by date only.</p>
  
  <p>How to convert date(string type) into date(date time ) in oracle. I am using select within select in other words nested select. Inner query returns string date time, and outer query unable to convert this to date time</p>