Only calculate measure for rows with data

[Nielf]

I have simple table in Power BI, where I have created a measure (% Compliance error percentage) as Total error count / open opportunities:

% Compliance error percentage = 

DIVIDE(SUM('Data compliance'[Total error count]),
sum('Data compliance'[Open opportunities]),
0
)

The data is logged every two weeks (week 1, 3, 5 and so forth as per the table below).

This simple calculation works fine. However, instead of showing the 'error percentage' I would like to show the 'valid percentage' by subtracting the error percentage from 1. E.g., 'valid percentage' for week 1 will be 93,75%.   

The issue is that if I make a simple measure like this:

% Compliance valid percentage = 

1 - [% Compliance error percentage]

I will end up with values for all dates, also the ones where we haven't logged any data, since 1-0 will return a value. 

My question is now - is there a way I can limit the measure to only make the calculation for the rows that have data?

I have tried with varies IF statements but I haven't found a solution,. 

[Nielf]

Thanks for the link @mh2587. It explained the differences nicely and I produced a solution using ISBLANK().

IF(NOT(ISBLANK([% Compliance error percentage])), 1-[% Compliance error percentage])

[mh2587 · Accepted solution]

https://www.burningsuit.co.uk/how-dax-treats-nulls-zeros/

Follow this url how to handle null and zeros value in dax

[Nielf]

@mh2587 yes - that is working. However, is it possble to return 100% as 'valid percentage' if 'error percentage is 0?

[mh2587]

 if([% Compliance error percentage] <> Blank(),1 - [% Compliance error percentage])