Work with three arrays and insert with PHP in MySQL database

I have the following code:

foreach ( $_POST["num_cod"] as $num_cod) {
      echo $num_cod;
  }
  foreach ( $_POST["fec_cod"] as $fec_cod ) {
    echo $fec_cod;
  }
  foreach ( $_POST["nro_oper"] as $nro_oper ) {
    echo $nro_oper;
  }

Where the variables: $num_cod , $fec_cod and $nro_oper , are arrays with n elements each where the first element of the first array corresponds to the first element of the second and the first element of the third array Each column corresponds to a column in a table. What I need is that each element of each array in its corresponding column be loaded in the table of mention and that the relationship between the data be maintained. I have tried several ways but I have not obtained the expected results, this is:

• Making a INSERT for each foreach : all the variables are inserted but there is no data correlativity, that is, the elements of the first array are loaded in n rows, those of the second array in the following n rows, etc., filling the other fields with zeros.
• Nesting the foreach and a single INSERT for the three variables: 3.n repetitions of the data are loaded.
• Making INSERT out of foreach does not work either.

If someone can help me since the php.net documentation has not helped me too much. With array_merge() I could make a matrix with the three arrays but I would not know how to take them to the mysql table. The arrays always complicate me. I am very grateful for the time that the members of this forum use to help those we know less.

With:

echo $_POST['fec_cod'];
echo $_POST['nro_cod'];
echo $_POST['nro_oper'];

With:

if ( !empty($_POST["nro_cod"]) && is_array($_POST["nro_cod"]) ) {
  echo "<ul>";
  foreach ( $_POST["nro_cod"] as $nro_cod ) {
          echo "<li>";
          echo "Código: ",$nro_cod;
          echo "</li>";
   }
   echo "</ul>";

and it also works with the other two variables.