Question

I’ve seen there there are numerous ways to put the results of a SQL query into usable format (that is, variables).

If I have a targeted SQL query that I know will be returning a set of expected values, lets say querying a customer number to pull data, city, state, first and last name, etc..

Code example follows:

$example = '50';
$result = mysql_query("SELECT * FROM customers WHERE customer_ID = '$example'",$db);
while ($row = mysql_fetch_assoc($result)) {
  foreach ($row as $col => $val) {
    if ($col == 'firstname') {
      $customerfirstname = $val;
    }
  }
}

or another way:

$result = mysql_query("SELECT * FROM customers WHERE customer_ID = '$example'",$db);
$myResultArray = array();

while ($row = mysql_fetch_assoc($result))
  $myResultArray = $row;

  foreach ($myResultArray as $val) {
    $customerfirstname = $val['firstname'];
  }

That’s just two that I could think of.

Is one of the above methods preferable over the other? If so, why?

Is there an alternate method that is even more efficient than either of these?

Answer 1

Neither are preferred.

The foreach‘s are superfluous.

Since you know the fieldnames you need, you can just do:

while ($row = mysql_fetch_assoc($result)) {
    $customerfirstname = $row['firstname'];
}

If you do need to apply a conditional for some reason, you can test for the field’s existence in the array:

while ($row = mysql_fetch_assoc($result)) {
    if (isset($row['firstname'])) {
        $customerfirstname = $row['firstname'];
    }
}

Finally, since you appear to be selecting by primary key, the while loop is also unnecessary:

if ($row = mysql_fetch_assoc($result)) {
    $customerfirstname = $row['firstname'];
}