Expression question

[mwallman]

Hi I read in some QlikView documentation that:

date(max(ORDERDATE,'DD/MM/YYYY')) is 3 times faster than

max(date(ORDERDATE,’DD/MM/YYYY’) )

Can anyone please tell me why? This is better? There was no explanation when I read it at the time.

[petter]

It is due to the fact that the aggregation is done directly on a field. And then the Date() function is performed once at the end of the aggregation.

The second expression is an aggregation that needs to perform the function Date() on a field during aggregation. This slows it down - naturally.