title: When querying certain fields, only those users with data in every field are returned
body: <p>I wish to show a line-item for each user, regardless of whether they have a value for wpcf-dc-license-number, wpcf-dc-license-expiration, etc.</p>
  
  <p>Currently my results only display user line-items for those users who have all the fields fulfilled.</p>
  
  <pre><code>SELECT lx_usermeta.meta_value AS dc_license_number,
  lx_usermeta2.meta_value AS dc_license_expiration,
  lx_usermeta3.meta_value AS md_license_number,
  lx_usermeta4.meta_value AS md_license_expiration,
  lx_usermeta5.meta_value AS va_license_number,
  lx_usermeta6.meta_value AS va_license_expiration,
  lx_usermeta7.meta_value AS first_name,
  lx_usermeta8.meta_value AS last_name,
  lx_usermeta9.meta_value AS ltx_company
  
  FROM lx_usermeta
  JOIN lx_usermeta lx_usermeta2 ON lx_usermeta.user_id = lx_usermeta2.user_id
  JOIN lx_usermeta lx_usermeta3 ON lx_usermeta.user_id = lx_usermeta3.user_id
  JOIN lx_usermeta lx_usermeta4 ON lx_usermeta.user_id = lx_usermeta4.user_id
  JOIN lx_usermeta lx_usermeta5 ON lx_usermeta.user_id = lx_usermeta5.user_id
  JOIN lx_usermeta lx_usermeta6 ON lx_usermeta.user_id = lx_usermeta6.user_id
  JOIN lx_usermeta lx_usermeta7 ON lx_usermeta.user_id = lx_usermeta7.user_id
  JOIN lx_usermeta lx_usermeta8 ON lx_usermeta.user_id = lx_usermeta8.user_id
  JOIN lx_usermeta lx_usermeta9 ON lx_usermeta.user_id = lx_usermeta9.user_id
  
  WHERE lx_usermeta.meta_key = "wpcf-dc-license-number"
  AND lx_usermeta2.meta_key = "wpcf-dc-license-expiration"
  AND lx_usermeta3.meta_key = "wpcf-maryland-license-number"
  AND lx_usermeta4.meta_key = "wpcf-maryland-license-expiration"
  AND lx_usermeta5.meta_key = "wpcf-virginia-license-number" 
  AND lx_usermeta6.meta_key = "wpcf-virginia-license-expiration"
  AND lx_usermeta7.meta_key = "first_name"
  AND lx_usermeta8.meta_key = "last_name"
  AND lx_usermeta9.meta_key = "wpcf-ltx-company"
  </code></pre>
  
  <p>I have tried changing the JOIN to LEFT JOIN, FULL JOIN, FULL OUTER JOIN, placing UNION between the JOIN statements, but I'm not having any luck finding a way to have these fields joined without the exclusive requirement of having all the wpcf fields filled in.</p>
  
  <p>Thank you for your help!</p>
  
  <p>UPDATE:
  I have tested this code:</p>
  
  <pre><code>SELECT lx_usermeta.meta_value AS first_name, lx_usermeta2.meta_value AS last_name
  FROM lx_usermeta
  JOIN lx_usermeta lx_usermeta2 ON lx_usermeta.user_id = lx_usermeta2.user_id
  WHERE lx_usermeta.meta_key =  "first_name"
  AND lx_usermeta2.meta_key =  "last_name"
  </code></pre>
  
  <p>This will show all users one after another, even if they have only one or even neither of first_name or last_name.</p>
  
  <p>What could possibly be affecting the wpcf-* fields (custom fields) so that when I use the same syntax with them, I only receive results in which there is data for all the wpcf-fields?</p>