title: Retrieving Value from Another Row in Spotfire
body: <p>I am attempting to reference a value in another row for a particular column of data in Spotfire.  As an example, I would like to reference the sales month where the quantity of sales of bronze widgets was equal to the number of Gold Widgets. I've included a column below to show the data I need, "Month Where Bronze Sales = Gold Sales"</p>
  
  
  
  <pre class="lang-all prettyprint-override"><code>Sales Month        Cumulative Bronze Widgets             Cumulative Gold Widgets              Month Where Bronze Sales = Gold Sales
     1/1/2017                                     0                                 1                                              2/1/2017
     2/1/2017                                     1                                 2                                              4/1/2017
     3/1/2017                                     1                                 2                                              4/1/2017
     4/1/2017                                     2                                 3                                              5/1/2017
     5/1/2017                                     3                                 3                                              5/1/2017
     6/1/2017                                     4                                 3                                              5/1/2017
  </code></pre>
  
  <p>I need to accomplish this with an expression without using a script or inserting another table. Is this possible? I've tried the following and other "Over" functions without success for "Month Where Bronze Sales = Gold Sales"</p>
  
  
  
  <pre class="lang-sql prettyprint-override"><code>Case When Max([Cumulative Bronze Widgets]) over ([Sales Month])= [Cumulative Gold Widgets] Then Max([Sales Month]) Over ([Cumulative Bronze Widgets]) else NULL End
  </code></pre>