SQL Selecting one record from two tables, then update it

Question

I have two tables in my database, Users and Staff. Self explanatory I hope. Attributes common to both tables are:

---

| id | Reference | First_Name | Last_Name | Email |...

In my user.php file, there's a lot of functions used to update an attribute for a user's account. Currently it's very inefficient because I have had to split the queries to check if a user is in the Users table or the Staff table, then do the same thing in order to push any changes back to my database.

I'd like a single query to do the hard work of finding the record from two tables.

    //Check the USERS table first
    $LocateAccount__UsersTable_Query = $CTDatabase->prepare("SELECT * FROM Staff WHERE Reference='$Account_Reference'");
    $LocateAccount__UsersTable_Query-> execute();
    $LocateAccount__UsersTable_Count = $LocateAccount__UsersTable_Query->rowCount();

if ($LocateAccount__UsersTable_Count > 0){
    //Fetch the user's record
    // echo "USER IS USER";
      $Located_Account = $LocateAccount__UsersTable_Query->fetch(); 


  } else {
    //Account not found in USERS table, so check STAFF table
    $LocateAccount__StaffTable_Query = $CTDatabase->prepare("SELECT * FROM Staff WHERE Reference='$Account_Reference'");
    $LocateAccount__StaffTable_Query-> execute();
    $LocateAccount__StaffTable_Count = $LocateAccount__StaffTable_Query->rowCount();

    if ($LocateAccount__StaffTable_Count > 0){
      //Account has been found in the USERS table
      $Located_Account = $LocateAccount__StaffTable_Query->fetch(); 
      //Fetch the STAFF user's record
      // echo "USER IS STAFF";

    } else {
      echo 'An error message goes here..';
    }

Question 1: How can I find a user in either Users or Staff tables in one single query?

Question 2: How can I then UPDATE an attribute on a single entry in one of these tables in a single query?

Things I am looking into, using EXISTS, but I get errors when trying the code in Sequel Pro: SQL Data from One of Two Tables

Answer 1

Assuming 'Reference' column will have unique values across both the tables, you can use UNION operator to search both the tables with same value, eg:

select Reference, first_name, last_name from users where Reference = ?
UNION
select Reference, first_name, last_name from staff where Reference = ?

You can also update both the tables in one query using join , eg:

UPDATE users,staff SET table1.col=a,table2.col2=b
WHERE users.reference = ?;