return "-" as the change if there is no last result data

[Hayoung]

My code below return the change(current result-last result) for most case. However, if there is no last result data, then it will return the current result instead of the change. How could i just return "-" if this case?

Q Change(vs Last Survey) = var _date= maxx(filter('Survey Data Score', 'Survey Data Scores(%)'[Facility Name + ID] = earlier('Survey Data Score'[Facility Name + ID]) && 'Survey Data Scores(%)'[Survey Close Date] < earlier('Survey Data Score'[Survey Close Date]) ), 'Survey Data Score'[Survey Close Date])

var _score='Survey Data Score'[question]- maxx(filter('Survey Data Score', 'Survey Data Score'[Facility Name + ID] = earlier('Survey Data Score'[Facility Name + ID]) && 'Survey Data Score'[Survey Close Date] =_date ), 'Survey Data Score'[question])

return

IF('Survey Data Score'[Current/Last]="Current Survey", IF(_score='Survey Data Scores(%)'[question],0,ROUND(_score,1) ))

[v-zhangti]

Hi, @Hayoung 

Can you provide sample data for testing? Sensitive information can be removed in advance. What kind of expected results do you expect? You can also show it with pictures. I look forward to your response.

Best Regards,

Community Support Team _Charlotte

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