Today marks my first blogging of “Best Of QlikCommunity” (BOQC) where I plan to highlight what I find to be particularly useful or interesting posts on the QlikCommunity Forums.
There are cases when the ApplyMap() function is a very useful alternative to Join. For some time I have noticed both Oleg Troyansky and Michael Nordstrom dropping this hint on QlikCommunity but I never quite understood the power of the technique until a post Oleg made today:
http://community.qlikview.com/forums/p/16017/62222.aspx#62222
The original forum question was how to multiply two fields from different tables to derive a new calculated field. The tables share a common key field.
I usually would have approached this with two Joins. That approach works, but sometimes I don’t really want my data model to reflect Joined tables. I just want to do the calculation.
If you want to see the ApplyMap() solution, read the post linked to above. The thread explains it better than me repeating it here.
As I’ve wrote in the QlikView thread, you should consider lookup() for better use.
Ralf,
I updated the QlikCommunity thread with my experience with lookup. I agree that lookup() is handy, but I find it too slow when processing larger quantities of rows — 10K +.
-Rob
Link moved:
http://community.qlikview.com/message/28479#28479