title: Left join without multiple rows from right table
body: <p>I have two tables (<code>User</code> and <code>Salary</code>). I want to do a <code>left join</code> from <code>User</code> to <code>Salary</code>. For each user I want their name and salary. In case they have no salary that field can be left empty. So far a left join is all we need. But I only want one row per user. Due to some defects there can be several salaries for one user (see table salary). I only want one row per user which can be selected randomly (or top 1). How do I do that? The expected output is presented in the bottom.   </p>
  
  <p>User Table:   </p>
  
  <pre><code>User Name
  1    Adam
  2    Al
  3    Fred
  </code></pre>
  
  <p>Salary Table</p>
  
  <pre><code>User  Salary
  1     1000
  2     2000
  2     2000
  </code></pre>
  
  <p>Expected table:</p>
  
  <pre><code>User Name  Salary
  1    Adam  1000
  2    Al    2000 
  3    Fred  null
  </code></pre>