Count distinct Policy Number if particular field is null ?

[suvechha_b]

Hi All ,

How to count distinct Policy Number if 'POLICY_HOLDER_EMAIL_ADDRESS' field is null.

Sample model attached.

[sunny_talwar]

May be this

Count(DISTINCT {<[Policy Number] = {"=Len(Trim(POLICY_HOLDER_EMAIL_ADDRESS)) = 0"}>} [Policy Number])