title: ORA-30926: unable to get a stable set of rows in the source tables in the following query
body: <pre><code>MERGE INTO tbl_brk_sch_cat_mappin_temp bsc
  USING  lookup l
  ON (l.lookup_id = bsc.catery_id) 
  WHEN MATCHED THEN
  UPDATE SET bsc.new_category=l.longname where  bsc.created_date=to_date('10/30/2015','MM/DD/YYYY');
  </code></pre>
  
  <p>I've ran tbl_brk_sch_cat_mappin_temp it has data and also I've ran the 'lookup' table  which also has data.</p>
  
  <p>Why would this error come and how can it be resolved?</p>