distinct values of

This is a text function that appends the non-blank values of a single attribute across the episodes of a case together, separated by commas. The values are arranged in alphabetical order, and only distinct values are included (case sensitivity is taken into account).

For example, suppose we had the following case fragment:

              01 Jun 09    20 Jun 09    30 Jun 09    15 Oct 09    02 Nov 09
Orders           TSH                       CHOL         HFBC         HFBC

Then the expression

distinct values of Orders

would evaluate to

CHOL, HFBC, TSH