如何在一个.php文件中获取两个html表单？

Now i have 4 buttons on my page. They define different parameters. What i want to do, is use php switch case, and after pressing for example button1 i want the datetimepicker, and a chart appear as well. I read that i can manage with that problem using two html forms in one php file adding form id, but im only getting the first form to work properly while the second one seems to fail with sending the data using POST method. Below how i try to do this:

<form id="switch" action="data-from-database.php" method="post">
  <h2 align="center">Wybierz interesujący Cię przedział
    czasowy</h2></br>
  <div id="pudlo">
    <input type="submit" name="przycisk"
           class="input_wykresy" value="temperatura" form="switch">
    <input type="submit" name="przycisk"
           class="input_wykresy" value="wilgotność" form="switch">
    <input type="submit" name="przycisk"
           class="input_wykresy" value="ciśnienie" form="switch">
    <input type="submit" name="przycisk"
           class="input_wykresy" value="irradiancja" form="switch">
  </div>
</form>

<?php
//PHP part here is what i want to appear on the page after using switch
switch ($_REQUEST['przycisk'])
{
  case "temperatura":
    //Once again HTML part
    ?>
    <form id="picker" action="data-from-database.php" method="post">
      <input type="text" name="from_date"
             id="from_date" class="input_wykresy1" placeholder="Od" autocomplete="off">
      <input type="text" name="to_date" id="to_date"
             class="input_wykresy1" placeholder="Do" autocomplete="off">
      <input type="submit" name="filter" id="filter" value="Wyszukaj"
             form="picker" class="input_wykresy"/>
    </form>
<?php
    if (isset($_POST["from_date"], $_POST["to_date"]))  // php code which i want to work in case
    {
      $handle = $link->prepare("SELECT temperatura, czaspomiaru FROM Pomiary
                                WHERE czaspomiaru BETWEEN'" . $_POST["from_date"] . "' AND
                                '" . $_POST["to_date"] . "'");
    }
    $dataPoints = [];
    //Best practice is to create a separate file for handling connection to database
    try
    {
      // Creating a new connection.
      // Replace your-hostname, your-db, your-username, your-password according to your database
      $handle->execute();
      $result = $handle->fetchAll(\PDO::FETCH_OBJ);
      if ($result)
      {
        foreach ($result as $row)
        {
          array_push($dataPoints, ["label" => $row->czaspomiaru, "y" =>
            $row->temperatura]);
        }
      }
      else
      {
?>
    <div>
      <h2>
        <center>Nie znaleziono pasujących rezultatów</center>
      <h2>
    </div>
<?php
      }
      $link = null;
    }
    catch (\PDOException $ex)
    {
      print($ex->getMessage());
    }
}

First form working properly, which i tested on buttons. Second one doesnt work, because when i press the submit button refering to datetimepickers, nothing shows on chart i assume no data been sent. I wonder how can i get the second form working?

You might want a hidden field holding the name/value pair of the button taking you to the subform since the button is not part of that form.

<form id="picker" action="data-from-database.php" method="post">
  <input type="hidden" name="przycisk" value="temperatura">
  <input type="text" name="from_date"
         id="from_date" class="input_wykresy1" placeholder="Od" autocomplete="off">
  <input type="text" name="to_date" id="to_date"
         class="input_wykresy1" placeholder="Do" autocomplete="off">
  <input type="submit" name="filter" id="filter" value="Wyszukaj"
         form="picker" class="input_wykresy"/>
</form>

Or, since you do not use the submit button name="filter" in your PHP code, you could just alter that button.

<form id="picker" action="data-from-database.php" method="post">
  <input type="text" name="from_date"
         id="from_date" class="input_wykresy1" placeholder="Od" autocomplete="off">
  <input type="text" name="to_date" id="to_date"
         class="input_wykresy1" placeholder="Do" autocomplete="off">
  <input type="submit" id="filter" name="przycisk" value="temperatura"
         form="picker" class="input_wykresy"/>
</form>

Consider using four radio buttons (instead of four submit buttons). Your site visitor(s) can select which radio button and submit. The code could easily be handled with if, elseif, else conditions, and the output could appear in one designated area, regardless of which radio button was selected.

<form id="switch" action="data-from-database.php" method="post">
  <h2 align="center">Wybierz interesujacy Cie przedzial
    czasowy</h2></br>
  <div id="pudlo">
    <input type="radio" name="przycisk" class="input_wykresy" value="temperatura">
    <input type="radio" name="przycisk" class="input_wykresy" value="wilgotnosc" >
    <input type="radio" name="przycisk" class="input_wykresy" value="cisnienie" >
    <input type="radio" name="przycisk" class="input_wykresy" value="irradiancja" >
    <input type="submit" value="submit">      
  </div>
</form>

<?php
  if (przycisk === "temperatura") {
    echo "yada";
  } elseif (przycisk === "wilgotnosc") {
    echo "yada";
  } elseif (przycisk === "cisnienie") {
    echo "yada";
  } else {
    echo "yada";
  }
?>