I have created a custom table in my wordpress project and I'm using wordpress sql queries to insert/update a user. When an email already exists, it should update the user with the same email, inserting a new user works, but updating one doesn't do anything. No errors either. Can anyone see what I'm doing wrong with my query? Here's my code:

global $wpdb;

        $fname = sanitize_text_field(esc_sql($_POST['fname']));
        $email = sanitize_email(esc_sql($_POST['email']));

        $uniqId = hexdec(uniqid());

        $prepare = $wpdb->prepare("SELECT * FROM `wp_registered_customers` WHERE email = %s", [$email]);
        $users = $wpdb->get_row($prepare);
        if(count($users) > 0){
            // wp_send_json_error(ErrorCodes::EMAIL_ALREADY_IN_USE, 400);
            $sql = $wpdb->prepare("UPDATE `wp_registered_customers` SET fnmme=%s, email=%s, step1=1, step2=0, step3=0 WHERE email=%s", 
            $result = $wpdb->get_results($sql);
        } else {
            $wpdb->insert('wp_registered_customers', array(
                'customer_id' => $uniqId,
                'fname' => $fname,
                'email' => $email,
                'step1' => 1,

1 Answer 1


There are 2 main issues in your code:

  1. Your $wpdb->get_row($prepare) will return either an object or a null, so you can't do if(count($users) > 0) because $users is not an array.

    To fix that, just use if ( $users ).

  2. There's a typo here: SET fnmme=%s — the field name should be fname.

So you should just need to correct those issues and your code would work as expected.

However, you should not use $wpdb->get_results() to run an UPDATE query, and instead,

  • You can use $wpdb->query().

  • Or in your case, you should use $wpdb->update() like so: (just replace the $sql = $wpdb->prepare(...); $result = $wpdb->get_results($sql); in your code with the code below)

            'fname' => $fname,
            'email' => $email,
            'step1' => 1,
            'step2' => 0,
            'step3' => 0,
        array( 'email' => $email )

    But, are you sure you want to set email to the value of $email? 🤔

Additionally, I don't think it's necessary to call esc_sql() here:

$fname = sanitize_text_field(esc_sql($_POST['fname']));
$email = sanitize_email(esc_sql($_POST['email']));
  • Thanks it works now, I used the ->update method. Will that automatically preven sql injection, or does that need additional code?
    – Jan
    Commented Jul 14, 2023 at 9:01
  • Yes, the update method will use the prepare method to prepare the query for a safe execution. The documentation also stated, "Both $data columns and $data values should be "raw" (neither should be SQL escaped)".
    – Sally CJ
    Commented Jul 14, 2023 at 9:11
  • Ah okay, sometimes an email is used multiple times, how do I make sure only the first found row with a specific email gets updated?
    – Jan
    Commented Jul 14, 2023 at 9:17
  • I have already answered your question, so additional questions should be asked via separate posts. But what you asked is a generic PHP/programming question and should instead be asked on Stack Overflow.
    – Sally CJ
    Commented Jul 14, 2023 at 13:29
  • Nonetheless, you'd want to use get_results() then, i.e. $users = $wpdb->get_results($prepare);, and use if($users && count( $users ) > 0). Then you'd want use the first item in the result, and then update by a unique field in your table, e.g. the customer_id field. So for example, pass array( 'customer_id' => $users[0]->customer_id ) as the 3rd parameter for that function. (If you need further assistance, you should post a new question)
    – Sally CJ
    Commented Jul 14, 2023 at 13:33

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