GROUP BY in Postgres - no equality for JSON data type?

Question

I have the following data in a matches table:

5;{\"Id\":1,\"Teams\":[{\"Name\":\"TeamA\",\"Players\":[{\"Name\":\"AAA\"},{\"Name\":\"BBB\"}]},{\"Name\":\"Tea         


        

Answer 1

Shorter, faster and more elegant with a LATERAL join:

SELECT DISTINCT ON (t.team->>'Name') t.team
FROM   matches m, json_array_elements(m.match->'Teams') t(team);
ORDER  BY t.team->>'Name', m.id DESC;  -- to get the "last"

If you just want distinct teams, the ORDER BY can go. Related:

• Query for element of array in JSON column
• Query for array elements inside JSON type

JSON and equality

There is no equality operator for the json data type in Postgres, but there is one for jsonb (Postgres 9.4+):

• How to query a json column for empty objects?