title: SQL query comparison
body: <p>1) <code>select name from city where countrycode="JPN" ;</code></p>
  
  <p>2) <code>select name from city where countrycode='JPN' ;</code></p>
  
  <p>3) <code>select name from city where countrycode="jPn" ;</code></p>
  
  <p>all the above queries are working in query 2 i am using single quotes and in 3 query i am using mixture of upper case and lowercase character . why it is producting correct output??.</p>