title: How to select most frequent value in a column per each id group?
body: <p>I have a table in SQL that looks like this:</p>
  
  <pre><code>user_id | data1
  0       | 6
  0       | 6
  0       | 6
  0       | 1
  0       | 1
  0       | 2
  1       | 5
  1       | 5
  1       | 3
  1       | 3
  1       | 3
  1       | 7
  </code></pre>
  
  <p>I want to write a query that returns two columns: a column for the user id, and a column for what the most frequently occurring value per id is. In my example, for user_id 0, the most frequent value is 6, and for user_id 1, the most frequent value is 3. I would want it to look like below:</p>
  
  <pre><code>user_id | most_frequent_value
  0       | 6
  1       | 3
  </code></pre>
  
  <p>I am using the query below to get the most frequent value, but it runs against the whole table and returns the most common value for the whole table instead of for each id. What would I need to add to my query to get it to return the most frequent value for each id? I am thinking I need to use a subquery, but am unsure of how to structure it.</p>
  
  <pre><code>SELECT user_id, data1 AS most_frequent_value
  FROM my_table
  GROUP BY user_id, data1
  ORDER BY COUNT(*) DESC LIMIT 1
  </code></pre>