title: Update Query With Joins and Group by Clause
body: <p>I have the following query and I'm trying to update table1 with the Total amount.
  Is there anyway to do this in 1 step?</p>
  
  <pre><code>select e.id
       , p.id
       , case  
           when count(distinct e.item) = 1 then 100
           when count(distinct e.item) = 2 then 150
           when count(distinct e.item) = 3 then 200
           when count(distinct e.item) = 4 then 225
           when count(distinct e.item) = 5 then 275
           when count(distinct e.item) = 6 then 325
           when count(distinct e.item) = 7 then 375
           when count(distinct e.item) = 8 then 450
           when count(distinct e.item) = 8 then 470
         end as TotalPay
    from table1 p 
    join table2 e on e.id = '111111'
                 and p.id=e.itemid
  group by e.id, p.id
  </code></pre>