title: how to delete duplicated value from table
body: <p>I had a table with some duplicate values. I have removed the duplicates by grouping on all the columns and inserting this into a temp table. Then deleting from the main table and inserting the data from the temp table.</p>
  
  <p>However there are some further values that should not be in the table which I am unsure of how to remove. </p>
  
  <p>So below is an example of my data. So for each name and dateFac there should be only one value for a factor, not two like we have for bbb_u</p>
  
  <pre><code> factor    value     name       dateFac
   bbb       -0.25     John       2017-01-01
   bbb_u     -0.295    John       2017-01-01
   bbb_u     -0.25     John       2017-01-01
  </code></pre>
  
  <p>The bbb_u factor which has the same value as factor bbb is the row I wish to remove so my table should look like below,</p>
  
  <pre><code> factor    value     name       dateFac
   bbb       -0.25     John       2017-01-01
   bbb_u     -0.295    John       2017-01-01
  </code></pre>
  
  <p><strong>update</strong></p>
  
  <p>the rule which I need to use to determine which bbb_u row to delete is simply the one which has the same value as the bbb factor.</p>