In an SSRS report builder expression, I am trying to get the sum of a conditional count -

i want sum of count if count >=3. gives me sum of counts, regardless if <> 3:

=sum(iif(countdistinct(fields!encounter.value)>=3,1,0))

this produces th same result, total number of distinct encounters:

=sum(iif(countdistinct(fields!encounter.value)>=3,countdistinct(fields!encounter.value),nothing))

i want total number of distinct encounters if there 3 or more per person. grouping on person first, encounter id.

ex: person enc john 1 bob 4 sue 2 ann 3

total enc>=3: 2

based on requirement, if there not details rows under encounter, should directly compare fields!encounter.value instead of using countdistinct()

sum(iif(fields!encounter.value>=3,1,0))

if have multiple detail rows under encounter group level, requirement can't achieved because can't use aggregation function within aggregation function. means can't distinct encounter ids first, calculate total.