title: MYSQL & PHP - Return 1 result per IN variable, even if variables are not unique
body: <p>I am querying a database to return the <code>user_name</code> row, by <code>user_id</code>, with the following prepared statement in PHP:</p>
  
  <p><code>$stmt = $conn-&gt;prepare("SELECT user_name FROM users WHERE user_id IN (?,?,?,?,?,?,?,?,?,?)");</code></p>
  
  <p>If each of the variables in the <code>IN</code> statement are unique and in the database, I receive 1 <code>user_name</code> result for each variable. <strong>However</strong>, if the variables in my <code>IN</code> statement are not unique (2 of the user_id's are <code>foo</code>), I currently do not get a <code>user_name</code> result for each <code>IN</code> variable.</p>
  
  <p>How do I modify my prepared statement, such that even if all of my variables in my <code>IN</code> statement were the same, I would still receive 1 row per variable, with <code>null</code> being returned if the variable isn't found. </p>