SQL Join Statement To Update an Entire Column with PHP Loop - php

Question

I need to update an entire column with new unique phone numbers that live in a second table. I seem to be on the right track... but my loop logic is faulty.
I'm returning the matches correctly as far as I can tell, but when I try to update the entire column in the table it inserts the last phone number in every single row.
$query = "SELECT matched.duns, matched.new_p1, users_data.temp_duns
FROM matched
INNER JOIN users_data ON temp_duns
WHERE temp_duns = duns LIMIT 10";
$result = mysqli_query($connection, $query);
foreach ($result as $key => $val) {
if($val['duns'] === $val['temp_duns']) {
$final_query = "UPDATE users_data SET phone_number = " . $val['new_p1'];
$final_result = mysqli_query($connection, $final_query);
echo $counter . "DUNS From matched: " . $val['duns'] . " DUNS From users_data: " . $val['temp_duns'] . " NEW PHONE: ". $val['new_p1']. "<br>";
}
}
I'm a total newb but any help would be appreciated.

Answer 1

Simply run an update query in one call without looping and in MySQL INNER JOIN can be used:
UPDATE user_data u
INNER JOIN matched m ON u.temp_duns = m.temp_duns
SET u.phone_number = m.new_p1;
Or for the limit of 10:
UPDATE user_data u
INNER JOIN (SELECT * FROM matched LIMIT 10) m ON u.temp_duns = m.temp_duns
SET u.phone_number = m.new_p1;

Answer 2

The problem is that your query doesn't have a WHERE clause, so it's updating every row.
"UPDATE users_data SET phone_number = " . $val['new_p1'];
You need to limit it to just the row that you want to update.
"UPDATE users_data SET phone_number = " . $val['new_p1'] . " WHERE some_id = " . $some_id;
You could probably do the whole thing in a single query.
UPDATE table_to_be_updated
JOIN table_with_value_we_need ON whatever_joins_them
SET table_to_be_updated.column_we_want_to_fill = table_with_value_we_need.value_we_need;