I have a table that I am trying to save to an sql file using php.
The table has fields with NULL.
However when I try and loop through the table rows to save to file, the NULLs become blank strings, is there anything I can do to prevent this?
Below is a snippet of the code

```
$sql="SELECT * FROM myTable";
$sql_result=mysql_query($sql);
while ($row = mysql_fetch_array($sql_result,MYSQL_ASSOC)){
    $saveSql.=$row['myId'].",";
    $saveSql.="'".$row['myName']."',";
    $saveSql.=$row['myAge'].",";
}

$handle = fopen('database.sql', 'w');
fwrite($handle,$saveSql);

```

If there are NULL values, then they are not saved to file, they are saved as empty strings.