title: advantage of select query in from clause
body: <p>What is the advantage of using select clause in the from clause over normal select clause ?. For ex.</p>
  
  <pre><code>select name, age, address from emp where 
   empid = 12.
  </code></pre>
  
  <p>what is the advantage of below query over above query.</p>
  
  <pre><code> select A.name, A.age, A.address from (select
    * from emp where empid = 12) as A.
  </code></pre>
  
  <p>The inner query creates a temp view and from that result, the fields in the first query selected. Right ?. But the query mentioned in the top of this question can also be used to get the same result.</p>
  
  <p>What is the advantage? Thanks.</p>