Hi, I have a query that generates a result set of 5 columns. I need to compare this result set against a table that has the same 5 columns plus 1 more column that has a value for how each row will migrated to another database. I need to find the rows from the query which as yet don't have a value assigned in the table. I was told to do a left outer join between the query and the table on the matching 5 columns and then set where clause to filter for nulls in the additional column from the right table. Hence, this should show the rows not joined from the left table and therefore not having a value assigned in the additional column. This does return a result set, but I checked and it does show rows from the query which are actually in the right table. It's because some of the columns I'm joining on have nulls. How do I get around this? I was thinking I could concatenate the columns that potentially contain nulls in both the query and the table and do a left join on the concatenated columns and again filter for nulls in the additional column from the right table. Unless there is an easier way to tackle this. Any help would be greatly received. Thanks, Rob.