title: SQL total spent per customer
body: <p>this is my first time asking a question on here, and I can usually find what I need just from seaching, however this time I'm stuck and I'm hoping someone here can help.</p>
  
  <p>Here's the gist. I have created a database for a hair dressing studio. there are five tables. The only one's this question deals with is the Customers table (stores customer details), the ProductSales table (store details about each product sale, and HairCuts table, store details about each cut.</p>
  
  <p>I need a query that will list the total spent on both hair cuts and products for each customer in the customers table.</p>
  
  <p>I have two separate queries that work fine. Each one calculates the total spent by each customer for EITHER hair cuts or products. I need to somehow combine these into one that will show the total.</p>
  
  <pre><code>SELECT c.customer_ID, c.first_Name, c.last_name, 
  SUM(hc.cost) AS hc_sales_total
  FROM Customers c, HairCuts hc
  WHERE c.customer_ID = hc.customer_ID
  GROUP BY c.customer_ID;
  
  SELECT c.customer_ID, c.first_Name, c.last_name, 
  SUM(ps.cost) AS ps_sales_total
  FROM Customers c,ProductSales ps
  WHERE c.customer_ID = ps.customer_ID
  GROUP BY c.customer_ID;
  </code></pre>
  
  <p>I believe the issues I am havng are stemming from the fact that, while all customers have purchased at least one hair cut, not all have purchased products. Anyway, any help would be much appreciated.</p>