$result = mysql_query($sql);

1. get all array

## good
##
while($tmp[] = mysql_fetch_assoc($result));

## some good
##
while($list = mysql_fetch_assoc($result))
{
  $tmp[] = $list;
}

## not good
##
while($list = mysql_fetch_assoc($result))
{
  $tmp[] = &$list;
}

## not good
##
$size = mysql_num_rows($result);
for($i=0; $i<$size; $i++)
{
  $tmp[] = mysql_fetch_assoc($result);
}

## not good
##
$size = mysql_num_rows($result);
for($i=0; $i<$size; $i++)
{
  $tmp[] = &mysql_fetch_assoc($result);
}


2. get partial array

## good
##
while($list = mysql_fetch_assoc($result))
{
  ...
  ... = &$list['foo'];
}

## not good
##
$size = mysql_num_rows($result);
for($i=0; $i<$size; $i++)
{
  $list = mysql_fetch_assoc($result);
  ...
  ... = $list['foo'];
}

## not good
##
$size = mysql_num_rows($result);
for($i=0; $i<$size; $i++)
{
  $list = mysql_fetch_assoc($result);
  ...
  ... = &$list['foo'];
}