Beginner's question: I'm trying to manipulate *tuples* from two different attributes in a relation using Java to process the SQL (for a university non-assessed practical).
I have a relation with four attributes, including the name of a type of coffee, the sales it has that week and the total sales of the coffee. 

The code I am trying to create will update the sales and the total fields with new figures. It is meant to take both `totalSales` and `Sales` arrays, add them, then update both attributes in the relation accordingly. 

This is my code so far (I've cut out all obvious/unnecessary code):

```
String updateTotalString = "update COFFEES set TOTAL = ? set SALES = ? where COF_NAME = ?";

String [] coffees = {"Columbian", "Earl Grey", "Kenyan", "Nescafe"};
int [] totalSales = {400,650,340,1000};
int[] sales = {50,75,100,100};

updateTotal = con.prepareStatement(updateTotalString);
    for (int i = 0; i < len; i++)
    {
        updateTotal.setInt(1, (sales[i] + totalSales[i]));
        updateTotal.setInt(2, sales[i]);
        updateTotal.setString(3, coffees[i]);
        updateTotal.executeUpdate();
    }

```

Unfortunately, running this gives me an SQL syntax error, focusing on the first line (the `String updateTotalString`). I have a feeling it's to do with the fact I'm trying to do two sets in one line and have got the syntax wrong.  

Can anybody help me out?