Return column name and distinct values

Question

Say I have a simple table in postgres as the following:

+--------+--------+----------+
|  Car   |  Pet   |   Name   |
+--------+--------+----------+
| BMW    |           


        

Answer 1

With JSON functions row_to_json() and json_each_text() you can do it not specifying number and names of columns:

select distinct key as col, value as vals
from (
    select row_to_json(t) r
    from a_table t
    ) t,
    json_each_text(r)
order by 1, 2;

SqlFiddle.