Question

In many scripts, programmers check if the SELECT query has returned any record before running the corresponding while loop as

$result=mysql_query("SELECT * From table WHERE column='XX'");
if(mysql_num_rows($result)>0) {
    while($row=mysql_fetch_array($result)){
    ...
    }
}

Is this check necessary or useful at all? because when not returning any record, the while loop will not cycle. Can checking the number of returned rows improve the performance?

Answer 1

you usually do it for the case where no rows have returned, and you simply want to print out a nice message for the user. if you only have a while loop, you’ll need to keep a counter and that can get ugly.

so it’s there mainly for the

else {
  echo "No results found!";
}

😉