title: SELECTING records based on unique date and counting how many records on that date
body: <p>I have a table that I'm going to simplify. Here's what it looks like:</p>
  <pre><code>tid     session    pos       dateOn
  -----------------------------------------------
  1         23        0        12/24/2020 1:00:00
  2         23        1        12/24/2020 1:01:23
  3         12        0        12/24/2020 1:02:43
  4         23        2        12/24/2020 1:04:01
  5         23        3        12/24/2020 1:04:12
  6         45        0        12/26/2020 4:23:15
  </code></pre>
  <p>This table tells me that there were 2 unique sessions 12/24/2020 and 1 on 12/26.</p>
  <p>How do I write my SQL statement so that I get a result like this:</p>
  <pre><code>date             recordCount
  ----------------------------
  12/24/2020            2
  12/26/2020            1
  </code></pre>