When I run the profiler, the 'simple' stats include two different counts: one for "unique" values and the other for "Distinct" values.
I don't understand the difference between them.
Can someone please explain how I should interpret the case when:
Row Count = 658,645 (OK, I think I understand this one )
Null Count = 0 (I understand this one too )
Distinct Count = 5,097
Unique Count = 541
Duplicate Count = 4,556
"Distinct count" counts the number of distinct values of your column (SELECT DISTINCT ...)
"Unique count" counts the number of distinct values with only one instance. It is necessarily less or equal to "distinct counts"
"Duplicate count" count the number of values appearing more than once.
You have the relation:
"Duplicate count" + "Unique count" = "Distinct count"
a,a,a,a,b,b,c,d,e => 9 values, 5 distinct values, 3 unique values, 2 duplicate values.
Thank you for your support,