getting specific data from wordpress database table - php

Question

I am trying to use WordPress logged in user id which should search transaction_user_ID in the table wp_m_subscription_transaction.
The table has a column called transaction_user_ID and another called transaction_paypal_ID.
logic:if user id == transaction user id then get transaction paypal id
which should be passed to the url along with the user id email address
and the execute the url to get the a code - this is my final output
How this can be achieved?
The code which I am developing is like this which is obviously incomplete & error for the getting and using the database query
<?php $user_id = get_current_user_id();
$query = "SELECT * FROM $wpdb->;wp_m_subscription_transaction
if ($user_id ==$query) {
Get ur Code
}
else {
echo 'You are not logged in as user ';}?>

Answer 1

First, since you need the email address as well, get all the current user's details, not just the id, using wp_get_current_user().
Secondly, your query is wrong; you haven't closed the quotes, and have a stray semicolon. If I've read it right, you need something like:
select transaction_paypal_ID
from wp_m_subscription_transaction
where transaction_user_ID = [the user's ID]
If you're only getting a single value in a query, you can retrieve it with $wpdb->get_var()
If the query doesn't return a row, it doesn't necessarily mean the user isn't logged in. You can check if a user is logged in using is_user_logged_in().
Something like this should work. I haven't tested, and you'll have to build up the URL yourself.
<?php
if (is_user_logged_in()) {
$user = wp_get_current_user();
$paypal_id = $wpdb->get_var("select transaction_paypal_ID from wp_m_subscription_transaction where transaction_user_ID = " . (int) $user->ID);
if ($paypal_id) {
// Build up your URL here, with $paypal_id and $user->user_email
}
else {
echo 'No transaction found for the current user';
}
}
else {
echo 'You are not logged in';
}
?>

Answer 2

Try this query.
$query = "SELECT transaction_paypal_ID FROM wp_m_subscription_transaction where transaction_user_ID = ".$user_id;
$result = $wpdb->get_row($wpdb->prepare($query), ARRAY_A);
$transaction_paypal_ID = $result['transaction_paypal_ID'];

Answer 3

This code comes without warrant, because you've not provided database structure, field names, or many other factors.
However, treated as pseudo-code, this will get you going in the right direction.
$user_id = get_current_user_id();
// Global / bring in $wpdb, and the $table_prefix variables
global $wpdb, $table_prefix;
// Use $wpdb prepare to be sure the query is properly escaped
$query = $wpdb->prepare("SELECT * FROM " . $table_prefix . "m_subscription_transaction WHERE user_id = %d", $user_id);
// Turn on error reporting, so you can see if there's an issue with the query
$wpdb->show_errors();
// Execute the query
$results = $wpdb->get_results($query);
// Are there any records? If so, that means the user ID matched
if ($results) {
$row = $results[0];
// Get the data from the row
echo 'Get ur Code';
} else {
echo 'No records for this user.';
}