title: How to count duplicate entries in a column
body: <p>I have two tables:</p>
  
  <p>Provider:</p>
  
  <pre><code> PROV_NO      P_NAME
  ----------  ---------- 
    P10         ANTEL
    P20         BCORP
    P30         CBIZ
  </code></pre>
  
  <p>Service:</p>
  
  <pre><code>S_TYPE  PROV_NO   R_PRICE
  ------- -------- ---------
    1      P10       160
    2      P10       180
    3      P10       110
    1      P20       190
    2      P20       180
    3      P20       150
    4      P20       240      
    5      P20       195
    1      P30       190
    2      P30       210
  </code></pre>
  
  <p>I am trying to count the number of services each provider offers and to display the counts for each next to the providers name. So I want my output to be:</p>
  
  <pre><code> P_NAME     COUNT
  ---------  --------
   ANTEL        3
   BCORP        5
   CBIZ         2
  </code></pre>
  
  <p>My attempt:</p>
  
  <pre><code>select provider.p_name, count(distinct service.prov_no)
  from provider,service
  group by provider.p_name
  </code></pre>
  
  <p>I have tried a few ways, but I cant seem to separate the counts and make them unique for each p_name.</p>
  
  <p>Thanks.    </p>