SQL or PIG script to restructure a table to reflect Columns in repeating rows
<p>So I have a table </p>

<pre><code>ID Tag1 Tag2 Tag3
1   a    b
2   a    b    c
3   a
</code></pre>

<p>I would like to transform this table to </p>

<pre><code>ID Tag
1   a
1   b
2   a
2   b
2   c
3   a
</code></pre>

<p>using PIG latin or SQL?</p>