php - How to use mysql to find a field name of a record? -

pdo sql codes :

while($r = $q->fetch(pdo::fetch_assoc)){     $gg = join('</td><td>', $r);     echo "<tr><td>" . $no_count . "</td><td>" . $gg . "</td></tr>";     $no_count = $no_count + 1;       } 

variable $r record, how can echo field name of $r?

let's $r carry records 2 different fields "product" , "price". value of $r "apple", "130". how can add "usd" "130"?

i need like.... if $field_name == "$r['price']" { $r = join('usd', $r); };

thanks mike b, there :

while($r = $q->fetch(pdo::fetch_assoc)){             foreach ($r $name => $value) {                 if ($name == "price"){                      $r = "usd" . $value; // line got problem, how change value in array variable $r?                 }             }              $gg = join('</td><td>', $r);             echo "<tr><td>" . $no_count . "</td><td>" . $gg . "</td></tr>";             $no_count = $no_count + 1;               } 

array_keys($r) list of fields table since you're fetching associative array.

you can loop through $r:

foreach ($r $name => $value) {   print "$name: " . $value; } 

update

// line got problem, how change value in array variable $r?

$r[$name] = 'usd' . $value; 

make edit original name. since have key in $name variable foreach loop can set directly.