title: LEFT OUTER JOIN returns no rows
body: <p>I have two tables with the same key. I want to, in one SELECT, <strong>without subsequent manipulation of data in an internal table</strong>, retrieve all records in the left-hand table where there is NO CORRESPONDING record in the right-hand table (i.e. columns from the right-hand table would be empty).</p>
  
  <p>The most logical thing to do would be the following, but this does not compile, because you may not use a field from the right-hand side in an outer join in the WHERE clause:</p>
  
  <pre><code>  select e~equnr into lt_equnr
      from equi as e
      left outer join eqbs as b on e~equnr = b~equnr
      where e~matnr = material
        and b~b_werk = space.
  </code></pre>
  
  <p>An alternative that looks promising and compiles is this, but it does not work, as it brings back even those that have corresponding entries in the right-hand table:</p>
  
  <pre><code>  select e~equnr into table lt_equnr
      from equi as e
      left outer join eqbs as b on e~equnr = b~equnr
      and b~b_werk = space
        where e~matnr = material.
  </code></pre>
  
  <p>This option merely blanks out fields from the right-hand side, but still includes everything in the result set. This can be confirmed by selecting fields from the right-hand side.</p>
  
  <p>Another option, which also does not work, is using a sub-select:</p>
  
  <pre><code>  select e~equnr into table lt_equnr
      from equi as e
      where e~matnr = material
        and e~equnr not in ( select equnr from equi where equnr = e~equnr ).
  </code></pre>