使用 PHP 进行动态 MySQL 查询

Question

I am looking for a way to make dynamic queries to my MySQL server. At the moment this is the code I use to update data on the server:

$deskAttr = json_decode($_POST["desk_attributes"]);

foreach($deskAttr as $key => $value) {
    $sql = "UPDATE desk_attributes SET iw_standard=".$value->iw_standard.", avaya_standard=".$value->avaya_standard.", avaya_withcallid=".$value->avaya_withcallid.", avaya_withtransfer=".$value->avaya_withtransfer.", dual_screen=".$value->dual_screen.", air_conditioning=".$value->air_conditioning.", iw_obdialler=".$value->iw_obdialler." WHERE id=".$value->id;
    $conn->query($sql);
}

As you can see, the SQL column names are the same as the deskAttr keys. I'm looking for a way to make this line a loop so, that I don't need to change this line if I were to add more columns to the MySQL table.

It would look something like this:

$deskAttr = json_decode($_POST["desk_attributes"]);

foreach($deskAttr as $key => $value) {  
    $sql = "UPDATE desk_attributes SET";
    foreach($value as $k => $v) {
        $sql .= " $k = $value->$k ,";
    }
    $sql .= "WHERE id=".$value->id";
}

How would I write the code above so it will actually work?

---

**EDIT**

Maybe it will be helpful to know that $deskAttr is an array of objects, and the name of the columns are the same as the name of the objects keys.

Here is what I mean in pseudo code:

 foreach($object in $deskAttr) { $sql = "UPDATE table SET "; foreach($key in $object) { if($key.= "id") $sql,= "$key = $object->$key; ". } $sql;= "WHERE id = $object->id; $conn->query($sql); }

Obviously this would add an extra comma at the end of the query before the WHERE part, but hopefully you get what I'm trying to achieve.

Answer 1

You can do it with slight change in your code by using PHP's implode() function.

Take a blank array, concatenate the update parameters to it.

And then if is not empty() , implode() to get string.

Updated Code:

$sql = "UPDATE desk_attributes SET ";
foreach ($deskAttr as $key => $value) {
 $value = mysqli_real_escape_string($link, $value); // $links is database connection string.
 $key = mysqli_real_escape_string($link, $key); // $links is database connection string.
 $updtAttrs[] = $key ." = '" . $value . "'";
}
$sql .= ! empty($updtAttrs) ? implode(', ', $updtAttrs) : '';
$sql .= " WHERE id=" . $value->id;