First date with sales greater than 100 in TABLEAU - date

Question

I have a very Basic flat file with Sales by date and product names. I need to create a field for First sales day where sales are greater than 100 units.
I tried {FIXED [Style Code]: MIN([Prod Cal Activity Date])} but that just gives me the first day in the data the Style code Exists
I also tried IF ([Net Sales Units]>200) THEN {FIXED [Style Code]: MIN([Prod Cal Activity Date])}END but that also gives me the first day in the data the Style code Exists
DATA EXISTS PRIOR TO SALES DATE

Answer 1

You can use the following calculation:
MIN(IF([Net Sales Units]>100) THEN [Prod Cal Activity Date] ELSE #2100-01-01# END)
The IF([Net Sales Units]>100) THEN [Prod Cal Activity Date] ELSE #2100-01-01# END part of the calculation converts the date into a very high value (year 2100 in the example) for all the cases where the sales was more than 100 units. Once this is done, you can simply take a minimum of the calculated date to get the desired result. If you need this by style code, then you can add a fixed function in the beginning.
A few ways to simplify further if you like. They don't change the meaning.
You don't need parenthesis around boolean expressions as you would in C.
You can eliminate the ELSE clause altogether. The if expression will default to null in cases where the condition was false. Aggregation functions like MIN(), MAX(), SUM() etc silently ignore nulls, so you don't have to come up with some default future date.
So MIN(IF [Net Sales Units] > 100 THEN [Prod Cal Activity Date] END is exactly equivalent, just a few less characters to read.
The next possible twist has a bit of analytic value beyond just saving keystrokes.
You don't need to hard code the choice of aggregation function into the calculation. You could instead name your calculated field something like High Sales Activity Date defined as just
if [Net Sales Units] > 100 then [Prod Cal Activity Date] end
This field just holds the date for records with high sales, and is null for records with low sales. But by leaving the aggregation function out of the calculation, you have more flexibility to use it in different ways. For example, you could
Calculate the earliest (i.e. Min) high sales date as requested originally
Calculate the latest high sales date using Max
Filter to only dates with high sales by filtering special non-null values
Calculate the number of high sales dates using COUNTD
Simple little filtering calculations like this can be very useful - so called because of the embedded if statement effectively filters out values that don't match the condition. There are still null values for the other records, but since aggregation functions ignore nulls, you can think of them as effectively filtered out by the calculation.