MYSQL ON DUPLICATE KEY UPDATE not working as intended [duplicate] - mysql

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This question already has answers here:
Insert into a MySQL table or update if exists
(12 answers)
Closed 2 years ago.
My app automatically checks when the customer logs in and only gives back one access_token and one shop values.
Below is the table with headings and a row of example data
access_token
shop
111111111
shop1
Sometimes a new customer installs the app and a new shop and access_token is created and I need to INSERT all new data in each column.
Other times the customer has re-installed the app so the shop exists but the access_token has changed and I need to update it.
How do I INSERT if none exist, but UPDATE if a value (shop) exists and another (access_token) doesn't when I am only given a single value of each?
I have attempted with ON DUPLICATE KEY UPDATE below where the shop is the same but the access_token has changed, but because I only get given one access_token to check when the customer logs in to the app it would just insert and not update.
INSERT INTO customers (access_token, shop)
VALUES(111, "shop1")
ON DUPLICATE KEY UPDATE access_token=111
I have attempted an example below where the shop is the same but the access_token has changed, however, I keep getting syntax errors. Please help, thank you.
SELECT EXISTS(SELECT shop FROM customers WHERE shop = 'shop1') AS sp,
NOT EXISTS (SELECT access_token FROM customers WHERE access_token = '{999999999}') AS tk
IF sp AND tk = 1
UPDATE customers
SET access_token='999999999'
WHERE shop = 'shop1';
ELSEIF NOT EXISTS (SELECT shop FROM customers WHERE shop = 'shop1') THEN
INSERT INTO customers (access_token, shop)
SELECT * FROM (SELECT '999999999', 'shop1') AS tmp;
END IF;

Answer 1

Are you using purely MySQL? I have made a signup and login page before as part of a web app and used Php to do this. I believe you can use Php for apks so I will write in Php, but you should be able to translate to your language with ease.
<?php
if (isset($_POST['signup-submit'])) { //this is so that the following can only be done on
the button press (name of it is signup-submit)
require 'dbh.inc.php';
$username = $_POST['Username'];
$email = $_POST['mail'];
$password = $_POST['pwd'];
$confirmpassword = $_POST['cpwd']; //this is all off the details of the user passed
through to be run through this script into the
database
if (empty($username) || empty($email) || empty($password) || empty($confirmpassword)) {
header("Location: ../index.php?error=emptyfields&uid=". $username. "&mail=". $email);
exit();
} //checking for empty fields
else if (!filter_var($email, FILTER_VALIDATE_EMAIL) && !preg_match("/^[a-zA-Z0-9 ]*$/", $username)) {
header("Location: ../index.php?error=invalidemail&uid");
exit();
}
else if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
header("Location: ../index.php?error=invalidemailuid");
exit();
}
else if (!preg_match("/^[a-zA-Z0-9 ]*$/", $username)) {
header("Location: ../index.php?error=invaliduid&email=". $email);
exit();
}
else if ($password !== $confirmpassword) {
header("Location: ../index.php?error=checkpasswords&mail=".$email. "&uid=".$username);
exit();
} //checking all characters used are only that which you allow
else {
$sql = "SELECT uidusers FROM users WHERE uidusers=?";
$sqly = "SELECT emailusers FROM users WHERE emailusers=?";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)) {
header("Location: ../index.php?error=sqlerror");
exit();
} //using prepared statements to insert user info
else {
mysqli_stmt_bind_param($stmt, "s", $username);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
$resultCheck = mysqli_stmt_num_rows($stmt);
if ($resultCheck > 0) {
header("Location: ../index.php?error=usertaken&mail=". $email);
exit();
} //checking for existing details
if (!mysqli_stmt_prepare($stmt, $sqlx)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
if (!mysqli_stmt_prepare($stmt, $sqly)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
else {
mysqli_stmt_bind_param($stmt, "s", $email);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
$resultCheck3 = mysqli_stmt_num_rows($stmt);
if ($resultCheck3 > 0) {
header("Location: ../index.php?error=emailtaken");
exit();
} //storing details
else {
$sql = "INSERT INTO users (uidusers, emailusers,
pwdusers, invcode) VALUES (?, ?, ?, ?) ";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
else {
$hashedpwd = password_hash($password, PASSWORD_DEFAULT); //hashing passwords
mysqli_stmt_bind_param($stmt, "sss", $username, $email, $hashedpwd);
mysqli_stmt_execute($stmt);
header("Location: ../index.php?signup=success"); //all details stored successfully
As for your access token, I would suggest adding a function to run a uniqid() function along with another function to check for existing tokens so that duplicates aren't made ( I did this for another similar reason to yours) and then using similar code as above to write that in.
I'm not sure what your shop ID is for but I have options for 2 eventualities:
If it's just a sort of ID, auto increment it in the database
If it's to show which shop the person entered, use foreign keys to link the column to a parent table with all the shops listed and set the relationship to cascade. Then make a button to switch shops that will
A) send an update to the database, overwriting the child column and row of the user
B) redirect the user to the new shop
(I have no idea why the second half of the code is green, but if you remove my comments you should be good, though I'd advise you to write your own code so that you can see how it works and adapt it to your own project)