Inserting/updating data into MySql database using php

Inserting/updating data into MySql database using php

I am trying to insert/update the MySql database depending on whether a
post already exists on the database (I am check this with a unique
user_id). The following works:
$select_query = "SELECT * ";
$select_query .= "FROM test ";
$select_query .= "WHERE user_id = '$user_id'";
$check_user_id = mysqli_query($connection, $select_query);
$query = "INSERT INTO test (";
$query .= " user_id, name, message";
$query .= ") VALUES (";
$query .= " '{$user_id}', '{$name}', '{$message}'";
$query .= ")";
$result = mysqli_query($connection, $query);
if ($result) {
echo "Success!";
} else {
die("Database query failed. " . mysqli_error($connection));
}
However, when I use the following code with an if/else statement, it does
not work anymore, although the console reports "Success!" (meaning $result
has a value). Any help would be greatly appreciated. Thanks.
$select_query = "SELECT * ";
$select_query .= "FROM test ";
$select_query .= "WHERE user_id = '$user_id'";
$check_user_id = mysqli_query($connection, $select_query);
if (!$check_user_id) {
$query = "INSERT INTO test (";
$query .= " user_id, name, message";
$query .= ") VALUES (";
$query .= " '{$user_id}', '{$name}', '{$message}'";
$query .= ")";
} else {
$query = "UPDATE test SET ";
$query .= "name = '{$name}', ";
$query .= "message = '{$message}' ";
$query .= "WHERE user_id = '{$user_id}'";
}
$result = mysqli_query($connection, $query);
if ($result) {
echo "Success!";
} else {
die("Database query failed. " . mysqli_error($connection));
}