title: perl waring : "Use of unintitialized value in string ne" for condition check for column with the null value
body: <p>I am trying to fetch certain column from a table , some of the column might have the null value.Hence before filling my main data, I am checking the hash for null value.As some of the key is having null value and giving warning. </p>
  
  <p>Is there any way to check if the hash key has no value in it to prevent warning.</p>
  
  <pre><code>    my $counter = 1;
      while ( my $hashRef = $queryHandle1-&gt;fetchrow_hashref) {
  
         foreach my $key (keys %{$hashRef} ) {
          if ( $hashRef-&gt;{$key} ne "" ) { #some of the coloumn of table has null value
                      #warning is coming for the if check
              $dbData{$counter}{$key} = $hashRef-&gt;{$key};
          }
          else {
              $dbData{$counter}{$key} = "";
          }
  
         }
         $counter++;
      }
  </code></pre>