title: Doing a WHERE IN on multiple columns in Postgresql
body: <p>I have a table 'answers' with an indexed 'problem_id' integer column, a 'times_chosen' integer column, and an 'option' column that's a varchar. Currently the only values for the 'option' column are 'A', 'B', 'C' and 'D', though those may expand later on. I want to increment by one the 'times_chosen' values of many (50-100) answers, when I know the problem_id and option of each of them.</p>
  
  <p>So I need a query that's something like:</p>
  
  <pre><code>UPDATE answers
  SET times_chosen = times_chosen + 1
  WHERE (problem_id, option) IN ((4509, 'B'), (622, 'C'), (1066, 'D'), (4059, 'A'), (4740, 'A')...)
  </code></pre>
  
  <p>Is this possible?</p>