title: PL/SQL: UPDATE inside CURSOR, but some data is NULL
body: <p>I'm still learning some of the PL/SQL differences, so this may be an easy question, but... here goes.</p>
  
  <p>I have a cursor which grabs a bunch of records with multiple fields. I then run two separate SELECT statements in a LOOP from the cursor results to grab some distances and calculate those distances. These work perfectly.</p>
  
  <p>When I go to update the table with the new values, my problem is that there are four pieces of specific criteria.</p>
  
  <pre><code>update work
          set kilometers = calc_kilo,
              kilo_test = test_kilo                                  
          where lc = rm.lc
          AND ld = rm.ld
          AND le = rm.le
          AND lf = rm.lf
          AND code = rm.code
          AND lcode = rm.lcode
          and user_id = username;
  </code></pre>
  
  <p>My problem is that this rarely updating because rm.lf and rm.le have NULL values in the database. How can I combat this, and create the correct update.</p>