title: what is scenario of using correlated and non correlated subquery
body: <p>Today I came to know across a feature of SQL Server known as correlated query and noncorrelated query.Then the certain question comes in my mind:</p>
  
  <p>What is difference between corelated and subquery in SQL Server? Is corleated subquery and non corelated subquery exist in SQL Server? </p>
  
  <p>if yes the difference of this and where we should use one of them? Explain the concept with simple illustration if you can.  </p>
  
  <p>I would like to know it.  </p>