Single Value Error

[DDenise]

Trying to calculate previous years sales to date but my formula is returning the below message:

A single value for column 'TtlValue' in table 'Rebates with Splits' cannot be determined. This can happen when a measure formula refers to a column that contains many values without specifying an aggregation such as min, max, count, or sum to get a single result.

Here is my formula: PYR = CALCULATE('Rebates with Splits'[TtlValue],SAMEPERIODLASTYEAR('Calendar'[Date]))

Current year formula works as shown below:

CYR = CALCULATE(SUM('Rebates with Splits'[TtlValue]),'Calendar'[Year]=Year(TODAY()))

[Ahmedx]

you forgot to add the SUM function here