title: Query for build at runtime according to program condition
body: <p>What points should be kept in mind while writing queries as under?</p>
  
  <p>$sql=" And two=2";</p>
  
  <p>$sql.=" And three=3";</p>
  
  <p>$sqlquery="select * from".$sql;</p>
  
  <p>I want to make complex queries like the example</p>