title: Insert into as select in redshift
body: <p>I have a table emp - </p>
  
  <pre><code>empno int(5) identity(1,1),
  ename varchar(50) default '-0',
  deptname varchar(50) default '-0'
  </code></pre>
  
  <p>When I use the statement - </p>
  
  <pre><code>insert into emp(ename, deptname) select ename, deptname from emp1;
  </code></pre>
  
  <p>I am getting all the values from emp1, but the null values are not substituted with <code>-0</code> but rather with <code>null</code>.</p>
  
  <p>What is the reason ?</p>