# DAX ParallelPeriod with dynamic interval set

• ### Question

• Hi,

i have the following DAX code to find the previous year premium in a table:

CALCULATE (
SUM ( 'Opl Quarterly As Of Amounts'[Gross Prem Inf] ),
PARALLELPERIOD ( 'OPL Date'[Date], -1, YEAR )
)

The table has year end values (Quarter 4) for all history and will have the latest quarter for the current year (i.e. it will have quarter 3 for 2018).

however, i want to make the -1 interval be dynamic based on the value in the quarter (1,2,3,4).  So if it's Quarter 1 or 2, i want to go back 2 years.  If it's 3 or 4, i want to go back 1 year.

I created the following:

CALCULATE (
SUM ( 'Opl Quarterly As Of Amounts'[Gross Prem Inf] ),
PARALLELPERIOD ( 'OPL Date'[Date], If('OPL Date'[Qrtr Num] = 1 || 'OPL Date'[Qrtr Num] = 2 ,-2, -1), YEAR )
)

but get the following error:

"A single value for column Qtr Num in OPL Date 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"

I can't seem to find the correct syntax to get it to work correctly.

Tuesday, November 13, 2018 8:21 PM

### All replies

• Hi ScottCabral,

Have a try this DAX expression:

```CALCULATE (
SUM ( 'Opl Quarterly As Of Amounts'[Gross Prem Inf] ),
PARALLELPERIOD ( 'OPL Date'[Date], If(SELECTEDVALUE('OPL Date'[Qrtr Num] )= 1 || SELECTEDVALUE('OPL Date'[Qrtr Num])= 2 ,-2, -1), YEAR )
)```

Regards,

Pirlo Zhang

MSDN Community Support&lt;br/&gt; Please remember to click &amp;quot;Mark as Answer&amp;quot; the responses that resolved your issue, and to click &amp;quot;Unmark as Answer&amp;quot; if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact &lt;a href=&quot;mailto:MSDNFSF@microsoft.com&quot;&gt;MSDNFSF@microsoft.com&lt;/a&gt;.

• Proposed as answer by Wednesday, November 21, 2018 9:21 AM
Wednesday, November 14, 2018 7:09 AM