I have a table of sampleIDs and tests. The sampleIDs are in a column and
appear multiple times because there are multiple tests done on each sample. I
want to find and copy a list of unique sampleIDs that have been analyzed on
another sheet.

table:
sampleID test
A x
B x
B z
A z
C y
C w
B w
A y


I want a list:
A
B
C

thanks