The Concatenate measure appends all values in the subset into a string, and the Unique Concatenate measure appends all the unique values into a string. That is, when you use Unique Concatenate, each value will only be included in the string once.

Example

Column A	Column B	Column C
1	1	1
1		3
1	3	3

With the columns from the table above, the following result would be given:

Column	Concatenate	Unique Concatenate
A	1,1,1	1
B	1,3	1,3
C	1,3,3	1,3