如何从数据库表中使用PHP $ row->中的变量？

Question

I have several fields in a PostgreSQL db table which I want to access in a PHP loop, since I want the same things to happen to each of them.

They are named similarly (3 lowercase letters), eg "mor", "gls", etc, and the various names are stored in an array called $fields.

The core of the code I'm using is as follows (I'm retrieving each row from the table, and then trying to loop through the fields):

$sql="select * from mytable order by id";
$result=pg_query($db_handle,$sql);
while ($row=pg_fetch_object($result))
{
  foreach ($fields as $field)
  {
    $myfield=$row->$field;
    <do something with $myfield>
  }
}

Unfortunately, the $row->$field doesn't work. I get the following:

PHP Notice:  Undefined property: stdClass::$mor
PHP Notice:  Undefined property: stdClass::$gls

I've tried various permutations of brackets and quotes, but I can't seem to find the magic dust. Is this doable?

Thanks.

Answer 1

为什么不使用pg_fetch_assoc而不是对象来获取数组，所以您可以这样做；

$myfield=$row[$field];

Answer 2

var_dump( $row );

并检查$row是否符合您的期望。

Answer 3

试试$myfield=$row->{$field}

Answer 4

You should iterate through the row, it will give you the column names (key) and their values (value)

you cant iterate through $fields, as it does not exist.

$sql="select * from mytable order by id";
$result=pg_query($db_handle,$sql);
while ($row=pg_fetch_object($result))
{
  foreach ($row as $key => $value)
  {
    $myfield=$value;
    <do something with $myfield>
  }
}