Sum Over unique identifier in Spotfire - bar-chart

Question

I am trying to create a bar chart that sums up values in a field, but only for each unique identifier. For instance, for my data:
Condition CT_ID Enrollment Company
I 5127 24 H
J 5127 24 H
P 5127 24 H
I 5127 24 O
J 5127 24 O
P 5127 24 O
L 27668 387 C
R 27668 387 C
D 38190 650 D
Q 38190 650 D
F 38785 30 A
E 39682 30 B
M 41818 17 I
O 44093 188 G
A 54850 18 K
G 59183 F
C 59891 266 J
G 61142 48 F
H 61425 28 L
K 61449 N
A 61793 12 E
N 61793 12 E
B 61910 120 M
B 61917 120 M
B 61961 130 M
Or, since I really want to eventually summarize these data by Condition, let me just show the above data resorted by Condition instead of [CT_ID].
Condition CT_ID Enrollment Company
A 54850 18 K
A 61793 12 E
B 61910 120 M
B 61917 120 M
B 61961 130 M
C 59891 266 J
D 38190 650 D
E 39682 30 B
F 38785 30 A
G 59183 F
G 61142 48 F
H 61425 28 L
I 5127 24 H
I 5127 24 O
J 5127 24 H
J 5127 24 O
K 61449 N
L 27668 387 C
M 41818 17 I
N 61793 12 E
O 44093 188 G
P 5127 24 H
P 5127 24 O
Q 38190 650 D
R 27668 387 C
The rows are duplicated by different values in Condition and Company. CT_ID is the identifier for the record.
I want to sum up my Enrollment column, but I will be overcounting. So I thought I could create a custom expression like :
Sum(Avg([Enrollment]) OVER ([CT_ID]))
But this is somehow not a valid expression. Where am I going wrong?
For my bar chart, I'd like to have the Condition as the category axis and the Enrollment as the value axis. The below table shows how the Enrollment value should be calculated. Focus on Conditions P, I, and J.
Condition Enrollment
A 30
B 370
C 266
D 650
E 30
F 30
G 48
H 28
I 24
J 24
K
L 387
M 17
N 12
O 188
P 24
Q 650
R 387
My current solution uses a rank function and only puts the enrollment info in the first row for each unique CT_ID, but that is just plain wrong when I start filtering data. For instance, imagine in my dataset above I only had an Enrollment value for the first row of CT_ID 5127. If I filter out Condition "I" (the one in the first row), now the Enrollment value is zero!
Any help you can provide would be greatly appreciated! I'm no expert on OVER expressions, so hopefully there is an easy solution!

Answer 1

This is too long to comment...
Can you provide some expected results? It looks as though each CT_ID can only have one value, so SUM of them distinctively would just be any one of the values... right? If not, what determines a duplicate?
Here is how you can accomplish what you were attempting in your code above--but from your test data isn't just going to give you the value of Enrollment since there each CT_ID seemingly only has one value (duplicated).
Sum([Enrollment]) over ([CT_ID]) / Count() OVER ([CT_ID])
You could also just use First()
First([Enrollment]) OVER ([CT_ID])
EDIT
Since you have some duplicates and some not... let's just split out the duplicates into the average of the number of duplicates there are. Insert this calculated column:
Max([Enrollment]) over (Intersect([CT_ID],[Condition])) / Count([Enrollment]) over (Intersect([CT_ID],[Condition]))
Then use this column in place of Enrollment in what ever expression you want to ignore duplicates, where a duplicate is the same Condition, CT_ID, and Enrollment value.
For example... the rows for Condition = P and CT_ID = 5127 will have 12 instead of 24.