title: MySQL outer join: why does selecting records in ON gives different results than selecting in WHERE?
body: <p>Why do these two queries give different results?</p>
  
  <p>This query gives all records regardless of the value of the deleted column.  It's as if that selection is ignored:</p>
  
  <pre><code>SELECT mcm.record_id, mc.category, mc.category_id, mc.deleted, mcm.member_id
  FROM mailing_category mc
      LEFT OUTER JOIN mailing_category_membership mcm
      ON mc.category_id = mcm.category_id
          AND mcm.member_id = 6346
          AND mc.deleted = 'false'
  WHERE mcm.record_id IS NULL
  </code></pre>
  
  <p>This query only selects records where the deleted column is false, which is what I want.</p>
  
  <pre><code>SELECT mcm.record_id, mc.category, mc.category_id, mc.deleted, mcm.member_id
  FROM mailing_category mc
      LEFT OUTER JOIN mailing_category_membership mcm
      ON mc.category_id = mcm.category_id
          AND mcm.member_id = 6346
  WHERE mcm.record_id IS NULL
          AND mc.deleted = 'false'
  </code></pre>
  
  <p>Why do the two queries give different results?  I'm using MySQL version 5.5.37.</p>