while/foreach/for get 3 results at a time?

I am trying to get 3 results out of a mysql d开发者_开发百科atabase at a time (so it would display 3 at a time)

So it would be something like

$sql = mysql_query("SELECT * FROM table");
while ($row = mysql_fetch_array($sql)) {
    print $row['username'];
    print $row['username2'];
    print $row['username3'];
}

but $row['username']; and $row['username2']; $row['username3']; would just be the first second and third results out of the mysql table.

and then it would repeat and $row['username']; and $row['username2']; and $row['username3']; would be the 4th, 5th and 6th and so on.

Any idea of how I could do this?

You could do this:

function mysql_fetch_n_rows($rs, $n)
{
  $rows = array();
  while ($n-- && ($row = mysql_fetch_array($rs)))
  {
    $rows[] = $row;
  }

  return $rows;
}

$rs = mysql_query("SELECT * FROM table");

while ($rows = mysql_fetch_n_rows($rs, 3))
{
    print $rows[0]['username'];
    print $rows[1]['username'];
    print $rows[2]['username'];
}

(Disclaimer: obviously you'd need to verify that you actually got 3 rows back. You might only get one or two.)

But I doubt you really need the above code. Generally it's much easier to do a ($i % 3) as some of the other answers suggest. I definitely do not post this answer because I think it's the best general solution, but only as an example of creating a general purpose function instead of trying to hard code this type of solution within the while loop.

You can use limit clauses,

select * from table limit 1, 3

then for the next 3,

select * from table limit 4, 3

(you might want to look up the syntax, I may have the order backwards)

To show just the three results, you can do like this:

$sql = mysql_query("SELECT * FROM table");

$count = 0;
while ($row = mysql_fetch_array($sql)) {
    $count++;
    if ($count === 3) break; 
    print $row['username'];
}

Or if you want, you can specify the LIMIT clause in your query to fetch just three records:

$sql = mysql_query("SELECT * FROM table LIMIT 3");

while ($row = mysql_fetch_array($sql)) {
    print $row['username'];
}

With LIMIT clause, you can also specify the start index and number of rows to be returned like this:

$sql = mysql_query("SELECT * FROM table LIMIT 4, 3");

The above query will return 3 rows starting from 4th row.

I think your logic is flawed, Steven.

Why do you need to access three records during one single iteration of a loop? This sounds like an illogical problem. My bet is that you're looking at a problem the wrong way. Can you provide a context for this problem?

While it does sound like your approach is somewhat illogical, I suppose you could store the results in an array, putting in three usernames at a time, and then outputting the data from the array instead. Like so:

$q = mysql_query("SELECT * FROM table");
$usernames = array();
while($d = mysql_fetch_assoc($q)) {
   $usernames[] = $d['username'];
   if(count($usernames) = 3) {
      sprintf('user 1: %s, user 2: %s, user 3: %s<br />', $usernames[0], $usernames[1], $usernames[3]);
      $usernames = array();
   }
}

The above is assuming that I understood your question correctly. I still don't quite know why you want to use this approach, though - you might be better off rethinking the logic behind this.

my 5 cents for use with templates
I am fond on using templates

<?
$data = dbgetall("SELECT username FROM table");
$data = array_chunk($data,3);
?>
<table>
<? foreach ($data as $chunk): ?>
 <tr>
<? foreach ($chunk as $row): ?>
  <td><?=$row['username']?></td>
<? endforeach ?>
 </tr>
<? endforeach ?>
</table>

$sql = mysql_query("SELECT * FROM table");

$count = 0;
while ($row = mysql_fetch_array($sql)) {
    $count++;
    if ($count % 3 == 0) print "<br/>" /* or any other way you want to break up the data */
    print $row['username'];
}