PHP PDO UPDATE variable fields using IF

Question

I have a function to update up to 3 fields in a mysql table. The function can receive all 3 fields to be updated or just 1 or 2

Right now I am doing it like this (it works) to construct MySQL statement.

if ($foo1){
   $mysql_set = '`foo1` = :foo1';}
if ($foo2){
   if ($mysql_set){$mysql_set .= ', ';}
   $mysql_set .= '`foo2` = :foo2';}
if ($foo3){
   if ($mysql_set){$mysql_set .= ', ';}
   $mysql_set .= '`foo3` = :foo3';}

$update = $db->prepare("UPDATE `bar` SET $mysql_set WHERE `id` = :id");

if ($foo1){
   $update->bindValue(':foo1', $foo1, PDO::PARAM_STR);}
if ($foo2){
   $update->bindValue(':foo2', $foo2, PDO::PARAM_STR);}
if ($foo3){
   $update->bindValue(':foo3', $foo3, PDO::PARAM_STR);}
$update->bindValue(':id', $id, PDO::PARAM_INT);
$update->execute();

As you can see I am repeating "if ($foo1 - $foo3){}" twice to construct this MySQL query. It looks redundant and wondering if there's a better way to handle this scenario.

Answer 1

You can give an associative array to execute() , instead of calling bindValue() separately for each parameter.

$param_array = array(':id' => $id);
$set_array = array();
if ($foo1) {
    $param_array[':foo1'] = $foo1;
    $set_array[] = "foo1 = :foo1";
}
if ($foo2) {
    $param_array[':foo2'] = $foo2;
    $set_array[] = "foo2 = :foo2";
}
if ($foo3) {
    $param_array[':foo3'] = $foo3;
    $set_array[] = "foo3 = :foo3";
}
if (!empty($set_array)) {
    $set_string = implode(", ", $set_array);
    $sql = "UPDATE bar SET $set_string WHERE id = :id";
    $update = $db->prepare($sql);
    $update->execute($param_array);
}

Answer 2

Try.

   if ($foo1){
       $mysql_set = '`foo1` = :foo1';
       $update = prepareStmt($db, $mysql_set);
       $update->bindValue(':foo1', $foo1, PDO::PARAM_STR);
    }
    if ($foo2){
       if ($mysql_set){$mysql_set .= ', ';}
       $mysql_set .= '`foo2` = :foo2';
    $update = prepareStmt($db, $mysql_set);
    $update->bindValue(':foo2', $foo2, PDO::PARAM_STR);
    }
    if ($foo3){
       if ($mysql_set){$mysql_set .= ', ';}
       $mysql_set .= '`foo3` = :foo3';
    $update = prepareStmt($db, $mysql_set);
    $update->bindValue(':foo3', $foo3, PDO::PARAM_STR);
    }


    $update->bindValue(':id', $id, PDO::PARAM_INT);
    $update->execute();

    function prepareStmt($db,$mysql_set){
        return $db->prepare("UPDATE `bar` SET $mysql_set WHERE `id` = :id");
    }