title: retrieve udf results in Hive
body: <p>In the following HiveQL code, I want to add partition to an existing table:</p>
  
  <pre><code>-- my_table was defined and partitioned by `dt string`, which is date
  -- now I want to add partition
  alter table my_table add if not exists
  partition (dt=current_date());   #FAILED: ParseException line 1:72 extraneous input '(' expecting ) near '&lt;EOF&gt;'
  
  alter table my_table add if not exists
  partition (dt=${current_date()});   # FAILED: ParseException line 1:60 cannot recognize input near '$' '{' 'current_date' in constant
  </code></pre>
  
  <p>However, the above code won't work, why? Any other way to do it?</p>