pass an array to a function to query database in PP - php

Question

I would like to pass an array with varying number of column names and the table to query database.
public function get_list() {
$list = func_get_args();
$table = array_pop($list);
$fields = implode(', ', $list);
$sql = "SELECT $fields FROM $table";
$data = array();
try {
$dbi = db::getInstance();
$stmt = $dbi->data->prepare($sql);
$stmt->execute();
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$data[]=$row[$fields];
}
return $data;
}
catch(PDOException $ex) {
die($ex);
}
}
The query gets the table and the right column, if there is only one.
But, if the array includes more than one column, it says:
Undefined index: value1, value2
Is there a valid way to use a comma separated string to query more than one column?
Thanks a lot!

Answer 1

Not sure what you're trying to do with the $fields in the loop. Your query will only return the fields that you specified. So your code would be:
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$data[] = $row;
}
But here are two ways to get the data as you are showing. Just assign in the loop:
while ($data[] = $stmt->fetch(PDO::FETCH_ASSOC)) {}
Or use a function to get all the rows:
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);
However, if I was going to take this approach I would pass in the table and fields (as an array) as specified arguments:
public function get_list($table, $fields)
To use the results outside of the function with dynamic fields, you would need to loop $rows to get them:
foreach ($this->model->get_list($fields, $table) as $row) {
foreach ($row as $field => $value) {
echo "$field contains $value";
}
}