title: SQL Query, Count with 0 count
body: <p>I have three tables: page, attachment, page-attachment</p>
  
  <p>I have data like this:</p>
  
  <pre><code>page
  ID    NAME
  1     first page
  2     second page
  3     third page
  4     fourth page
  
  attachment
  ID    NAME
  1     foo.word
  2     test.xsl
  3     mm.ppt
  
  page-attachment
  ID    PAGE-ID   ATTACHMENT-ID
  1     2         1
  2     2         2
  3     3         3
  </code></pre>
  
  <p>I would like to get the number of attachments per page <strong>also when that number is 0</strong>. I have tried with: </p>
  
  <pre><code>select page.name, count(page-attachment.id) as attachmentsnumber 
  from page 
      inner join page-attachment on page.id=page-id 
  group by page.id
  </code></pre>
  
  <p>I am getting this output: </p>
  
  <pre><code>NAME        ATTACHMENTSNUMBER
  second page  2
  third page   1
  </code></pre>
  
  <p>I would like to get this output:</p>
  
  <pre><code>NAME        ATTACHMENTSNUMBER
  first page   0
  second page  2
  third page   1
  fourth page  0
  </code></pre>
  
  <p>How do I get the 0 part?</p>