How to Get the Unique Values of a Column in a Google Docs Spreadsheet

I recently had the need to get all the unique values in cells within a column, by comma delimited.

Here’s the function I used:

=query(index(unique(trim(transpose(split(join(" ",A1:A&","),","))))),"select* where Col1 '' ")

I put his in B1 and it listed all the unique values from A:A and it automatically updates as you change the data in A:A