Unable to use if and median in Line chart expression

[#1]

!Hi,

I am new to Qlik view.This may seem like an amateur question.

I am building a line chart with year on the X-Axis which can be drilled down to month and median(JobEndTime-JobStartTime) on Y axis. I want the runtime for only one source system and so I am doing this

=if(source_system='XYZ',median(JobEndTime-JobStartTime),NULL())

The chart is blank and says No data to display. It looks correct but I at a loss as to why it isnt calculating the median.

Any help would be appreciated.

Thanks,

Sreekar

[rwunderlich]

The aggregation function is just a device to be able to use a Set expression. If there is only one qualifying row, It should give the same result.

-Rob