If you insert an 'exit script;' before the left join and after a reload check the table structure you will see that you have a synkey consisting of Datum AND Outgoing.
In the Outgoing table you have at that time one Row:
In OpenOrderTemp you have two rows:
Date Outgoing Intake
1-4-2009 1203 20102
Now, a left join on OpenOrderTemp takes the full data set of OpenOrderTemp and tries to join with Outgoing. As a join on Datum AND Outgoing CANNOT be made, the row of Outgoing 500 gets lost! The mistake as said is that Outgoing is used as key!! That's my interpretation for why it does not work.
I'm not exactly sure what your problem is but I think I know what's causing it.
If you load two identical tables, in terms of number of fields and field names, QlikView will automatically concatenate them.
When you do a Load * Resident xxx for example you will end up just doubling the rows in the table. I'm not sure if the join will be correctly applied there.
Either add a dummy field at some point like 1 as dummy, or use the NOCONCATENATE command which is described in the F1-help.