title: Is the viral PostgreSQL array slicing behavior standard?
body: <p>I was reading the <a href="http://www.postgresql.org/docs/current/static/arrays.html" rel="nofollow">PostgreSQL documentation</a>, and noticed that array slicing is kind of "<strong>viral</strong>" across dimensions:</p>
  
  <blockquote>
    <p>If any dimension is written as a slice, i.e., contains a colon, then
    all dimensions are treated as slices.</p>
  </blockquote>
  
  <p>For example the <code>[2]</code> in </p>
  
  <pre><code>SELECT schedule[1:2][2] FROM sal_emp;
  </code></pre>
  
  <p>does not mean the second element, but rather  means [1:2], so that the above is equivalent to:</p>
  
  <pre><code>SELECT schedule[1:2][1:2] FROM sal_emp;
  </code></pre>
  
  <p>This is rather confusing. The documentation does not say, and I was wondering if this behavior is defined in SQL standards or is it a postgres feature?</p>