Question

how to avoid mysql doing this (by itself or php script) , even if only one cell of a row is null or whitspaced like this: ' '.

we use regular way inserting data:

 $sql = "INSERT INTO `rows` (`results1`, `results2`) VALUES ('$res1', '$res2')";
 $res = mysqli_query($dbc, $sql);

Answer 1

1. Check it in PHP before sending the data.
2. Mark the columns of the table as NOT NULL and while inserting use the TRIM() function.