Pick up a single record for equal columns

Question

I have an example table:

produto    |   supermercado
----------------------------
    1      |        1
    4      |        2
    6      |        1
    5      |        1
    8      |        2
    7      |        3

I want to get all existing supermarkets in this table, without picking up repeat numbers. The result would be:

 supermercado
----------------
      1
      2
      3

Disregarding the repeated supermarkets. I couldn’t even begin with a query, because I do not know how to take these equal results.

Answer 1

To get the same results just use the command DISTINCT in the query.

So it doesn’t return repeated values, it would look great:

SELECT DISTINCT carrinhos.supermercado FROM carrinhos 

Answer 2

Use the word "distinct" in your sql query, it has exactly the function of eliminating repeated values in the query:

select distinct supermercado from tabela

Answer 3

to make the DISTINCT of a single column uses DISTINCT ON.

select distinct on (ed.id) ed.id, ed.nome from eventodisparo ed