PreviousDay for First Date in Dataset

Hi, S3 ;

Try it.

Previous Period Value = 
var _a= CALCULATE([Value Measure]
	                             ,DATESBETWEEN(
									 Dates[Date],
									 [Start of Previous Period],
				    				 [End of Previous Period]),
									 ALL(Dates))
var _diff2=DATEDIFF( CALCULATE(MIN('Dates'[Date]),ALLSELECTED(Dates)),CALCULATE(MAX('Dates'[Date]),ALLSELECTED(Dates)),DAY)
var _diff1=DATEDIFF( CALCULATE(MIN('Dates'[Date]),ALL(Dates)),CALCULATE(MIN('Dates'[Date]),ALLSELECTED(Dates)),DAY)
return IF(CALCULATE(SUM('Table'[value]),ALL('Table'))=_a||_diff1<_diff2,BLANK(), _a)

The final show:

Best Regards,
Community Support Team _ Yalan Wu
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