title: On Insert: column reference "score" is ambiguous
body: <p>I have the following command in postgresql:</p>
  
  <pre><code>INSERT INTO word_relations(word1_id, word2_id, score) VALUES($1, $2, $3)
  ON CONFLICT (word1_id, word2_id) DO UPDATE SET score = score + $3`)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>column reference "score" is ambiguous
  </code></pre>
  
  <p>I thought it was odd as I am only using one table. Any ideas?</p>