How do you work with drop down list to show a name, diff payment?

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I create a drop down list already, but it shows repeated name in it.
For example,
Name price suppliers
a 1 haha
b 2 hihi
a 2 haha
c 2 hihi
b 3 hihi

What I want to do is to create a drop down list with the names, which when I
click on the drop down list "a", all the "a" rows in the list goes to the
top.
ie
Name price suppliers
a 1 haha
a 2 haha
b 2 hihi
c 2 hihi
b 3 hihi

also in the drop down list which I created, the "a" is repeated several
times, I would like to make a list with no repeated name, ie in the drop down
list only appears as (a b c) not (a b a c b)

.