                     (<span style="color: #00ffff;">loop</span> for a in '(<span style="color: #cd8162;">"col1"</span> <span style="color: #cd8162;">"col2"</span>)
                           collect a
                           collect <span style="color: #98fb98; font-weight: bold;">:NULL</span>)))

<span style="color: #cd8162;">"UPDATE table1 SET E'col1' = NULL, E'col2' = NULL"</span>
</pre>
</div>

<p>
Lets think about it differently. What if we know the universe of columns we
want to select, but want to