title: COUNTIFS using REGEX as criteria
body: <p>I have this table below:</p>
  
  <pre><code>A       B           C
  Date .  Place       Person
  1/1  .  DOU,DORS    John
  1/1  .  DOMG,DOSP   Mark  
  2/1  .  DOU,DOSP    Alex
  1/1  .  DOU         John
  </code></pre>
  
  <p>I need a formula to <code>COUNTIF</code> "Date" is <code>1/1</code> and if inside "Place" the string "DOU" is present (I need to do that dynamically with multiple dates and strings, just using this example to simplify).</p>
  
  <p>So basically something like <code>COUNTIFS(B:B;"DOU";A:A;1/1) = TRUE</code></p>
  
  <p>I tried <code>COUNTIFS(B:B;"DOU";A:A;1/1)</code> but it didn't work out because it only works with exact matches and not partial strings. If I use <code>REGEXMATCH(B2;"DOU")</code> I get <code>TRUE</code>, however, I didn't find a way to insert <code>REGEXMATCH</code> inside <code>COUNTIFS</code> to make it in volume and dynamically. Is there a way to do that? If there is not, is there any way to make this operation?</p>
  
  <p>Also, I tried to use the answer in <a href="https://stackoverflow.com/questions/40515469/google-sheets-pattern-matching-regex-for-countif">this post</a> however it didn't work out right from the beginning. I'm trying to do <code>COUNTA(FILTER(B:B;REGEXMATCH(B:B; "DOU")))</code> but it is always 1 having or not having "DOU" in the column.</p>