Question

I want to show all text messages from db where id=$e ($err is an array).
Inserted the query into the foreach loop, it works well but it does extra work (does query for every value of array).
Is there any other way to do it (i mean extract query from foreach loop)?
My code looks like this.

foreach ($err as $e) 
{
$result = $db -> query("SELECT * from err_msgs WHERE id='$e'");
$row = $result -> fetch_array(MYSQLI_BOTH);
echo "<li><span>".$row[1]."</span></li>";
}

Answer 1

It is much more efficient to do this with implode() because it will only result in one database query.

if (!$result = $db->query("SELECT * FROM `err_msgs` WHERE `id`='".implode("' OR `id`='",$err)."'")) {
  echo "Error during database query<br />\n";
  // echo $db->error(); // Only uncomment this line in development environments. Don't show the error message to your users!
}
while ($row = $result->fetch_array(MYSQLI_BOTH)) {
  echo "<li><span>".$row[1]."</span></li>\n";
}