title: equi-join with mysql
body: <p>I'm trying to join a couple of tables where table videos has:</p>
  
  <pre><code>video_id
  user_id
  camera_id
  video_size
  video_datetime
  video_length
  video_url
  </code></pre>
  
  <p>and table cameras has:</p>
  
  <pre><code>camera_id
  user_id
  camera_hash
  camera_type
  camera_status
  camera_name
  camera_quality
  camera_user
  camera_pass
  camera_ip
  camera_port
  camera_url
  </code></pre>
  
  <p>So user_id and camera_id are common.  I'm trying to get data showing me the video size, date/time, length and camera name.  I can do this query:</p>
  
  <pre><code>SELECT videos.video_size, videos.video_datetime, videos.video_length,
  cameras.camera_name 
  FROM videos, cameras 
  WHERE videos.user_id = cameras.user_id 
  and videos.user_id=69 and cameras.camera_id=73
  </code></pre>
  
  <p>This is fine and gets me what I want but I need to calculate the number 73 (getting the user_id of 69 is not a problem).  So I can do this with:</p>
  
  <pre><code>SELECT camera_id from videos where user_id=69
  </code></pre>
  
  <p>This can return multiple values...so more processing.  I'm wondering if there is a better or more efficient way of doing this?</p>