title: Pivoting data in SQL and returning multiple associated columns
body: <p>I have a table that has the following fields: user_id, tag, tag_certification_date, tag_review_date, and tag_expiration_date. Each user number can have multiple tags, and in that case the user will have multiple rows in the table. One for each tag. There are 5 possible tags A, B, C, D, E.</p>
  <p>Example data</p>
  <pre><code>user_id   tag      tag_certification_date    tag_review_date    tag_expiration_date
  -------   ----    -----------------------   -----------------   --------------------
  001        A            2020-01-01              2020-06-01           2021-01-01
  001        B            2020-02-01              2020-07-01           2021-08-01
  001        C            2020-03-01              2020-08-01           2021-03-01
  </code></pre>
  <p>I have been able to use PIVOT to create a query that gets part of the way there but I'm having trouble including all of the date fields. I would like the query to return all the data for a user as a single row. So each tag and each tag's corresponding tag_certification_date, tag_review_date, and tag_expiration_date.</p>