title: how can join a query result set with an existing table?
body: <p>is there any way to avoid using tmp table?</p>
  
  <p>I am using a query with aggregate function (sum) to generate the sum of each product: 
  the result looks like this: </p>
  
  <pre><code>product_name | sum(qty) 
  product_1    | 100 
  product_2    | 200 
  product_5    | 300 
  </code></pre>
  
  <p>now i want to join the above result to another table called products. 
  so that i will have a summary like this: </p>
  
  <pre><code>product_name | sum(qty) 
  product_1    | 100 
  product_2    | 200 
  product_3    | 0 
  product_4    | 0 
  product_5    | 300 
  </code></pre>
  
  <p>i know 1 way of doing this is the dump the 1st query result to a temp table then join it with products table. is there a better way?</p>