title: How can I combine two data columns being used as separate filter controls into one single filter control without losing any values or data?
body: <p><strong>Question:</strong> How can I combine two data columns being used as separate filter controls into one single filter control without losing any values in Google Data Studio?</p>
  <ul>
  <li>I have attempted to use a calculated field of &quot;<strong>Coalesce([column1],[column 2])</strong>&quot;. This works mostly, however, sometimes values in the two columns are different and I am losing a few values that need to be included in the list.</li>
  <li>I am pulling data from BigQuery using a custom query. The two columns have different names, but have the same data type (text). Both columns are a part of the same table/data set</li>
  <li>I cannot list the specific values in this post because of data sensitivity, however I've included an example below.</li>
  <li>Sometimes when the columns are viewed side by side, one column contains a null value, OR both values could be the same, OR both values could be different</li>
  </ul>
  <p><strong>Example</strong></p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Column A</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>ABCDE</td>
  </tr>
  <tr>
  <td>FGHIJ</td>
  </tr>
  <tr>
  <td>KLMNO</td>
  </tr>
  <tr>
  <td>GGGG</td>
  </tr>
  </tbody>
  </table>
  </div><div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Column B</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>PQRS</td>
  </tr>
  <tr>
  <td>TUVW</td>
  </tr>
  <tr>
  <td>XYZA</td>
  </tr>
  <tr>
  <td>GGGG</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p><strong>Side by Side View - This is what the data looks like in tabular form:</strong></p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Column A</th>
  <th>Column B</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>null</td>
  <td>ABCDE</td>
  </tr>
  <tr>
  <td>PQRS</td>
  <td>FGHIJ</td>
  </tr>
  <tr>
  <td>TUVW</td>
  <td>null</td>
  </tr>
  <tr>
  <td>XYZA</td>
  <td>KLMNO</td>
  </tr>
  <tr>
  <td>GGGG</td>
  <td>GGGG</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>The coalesce function does not work because I am losing values where the two columns have different values - <strong>Coalesced Filter List will only include:</strong></p>
  <ul>
  <li>ABCDE</li>
  <li>PQRS</li>
  <li>TUVW</li>
  <li>XYZA</li>
  <li>GGGG</li>
  </ul>
  <p><strong>Missing Values:</strong></p>
  <ul>
  <li>FGHIJ</li>
  <li>KLMNO</li>
  </ul>
  <p><strong>Filter List Should Be:</strong></p>
  <ul>
  <li>ABCDE</li>
  <li>PQRS</li>
  <li>TUVW</li>
  <li>XYZA</li>
  <li>GGGG</li>
  <li>FGHIJ</li>
  <li>KLMNO</li>
  </ul>
  <p><strong>Question Reiterated:</strong> I want to combine these two columns as one list to be used in a single filter dropdown in Google Data Studio without losing values.</p>
  <p><strong>Sample Data</strong>:</p>
  <ul>
  <li>Data Set (<a href="https://docs.google.com/spreadsheets/d/1kh_WOUQK4V9fgiB-mYdAMN6xnBe8hcLgImTOTHuH4e8/edit?usp=sharing" rel="nofollow noreferrer">Google Sheets</a>)</li>
  <li><a href="https://datastudio.google.com/reporting/5c9e9a6b-df83-43a5-8a84-9151692c8525" rel="nofollow noreferrer">Google Data Studio</a> report</li>
  </ul>