仅当字段在Tableau中具有一个条目时才计数

Question

I am using tableau and am stuck in making the field of the following code unique.

"COUNTD(
IF NOT(ISNULL([firstBillingDate]))
THEN [msisdn]
ELSE NULL
END
)"

Basically its counting unique msisdn 's for all the columns which have firstbillingDate present (NOT NULL).

The problem is that one msisdn has more than one firstBillingDate . I want to count unique msidns which has only ONE firstbillingdate

Answer 1

Instead of using [firstBillingDate] in that calculation, create an LOD calc to only retrieve one date per msisdns.

{fixed [msisdns] : min([firstBillingDate]}

You can use max or min . I assumed you'd want min to return the earlier date for any multiple dates per msisdns. Now use this in your original calc.