How to cache mysql query in a variable?

Question

PHP

Good afternoon, I'm trying to cache the result of a query in redis, but it doesn't work, the variable is empty and I don't understand why

function get60_v1($_60n) {
  global $wpdb;
  ob_start();
  $s_1 = $wpdb->get_row(
    "
    SELECT *
    FROM learn 
    WHERE s_name = '".$_60n->name."'
  " 
  );
  return ob_get_clean();
}

$key_60_sql = $pname.':'.get_field('user_version');
if ($redis->exists($key_60_sql)) {
  $s_1 = $redis->get($key_60_sql);
} else {
$sql_60 = get60_v1($_60n);
  // вычисляете свой кусок, затем
  $redis->set($key_60_sql, $sql_60);
  $redis->expire($key_60_sql, 604800); // 1 неделя
  $s_1 = $redis->get($key_60_sql);
}

Tell me what I'm doing wrong?
PS Caching of html and PHP goes without problems
PS If the function is executed without attempting caching, then the variable receives data

function get60_v1($_60n) {
  global $wpdb;
  $s_1 = $wpdb->get_row(
    "
    SELECT *
    FROM learn 
    WHERE s_name = '".$_60n->name."'
  " 
  );
  return $s_1;
}

Answer 1

Solved the problem like this

$key_60_sql = $pname.':'.get_field('user_version');
if ($redis->exists($key_60_sql)) {
  $_s_3 = $redis->hgetall($key_60_sql);
  $s_3 = (object)$_s_3;
} else {
$sql_60 = $wpdb->get_row (
    "
  SELECT *
  FROM learn 
  WHERE s_name = '".$_60n->name."'
  "
  );
  $array = (array)$sql_60;
  // вычисляете свой кусок, затем
  $redis->hMSet($key_60_sql, $array);
  $redis->expire($key_60_sql, 604800); // 1 неделя
  $_s_3 = $redis->hgetall($key_60_sql);
  $s_3 = (object)$_s_3;
}

Answer 2

$60n- How is that? How about:
A valid variable name must begin with a letter or underscore and consist of any number of letters, numbers, and underscores.
https://www.php.net/manual/en/language.variables.b...