Just get one data if duplicate (not DISTINCT)

I have the following result from a query in mysql (headers: depicao, arricao):

EDDH, EDDK
EDFH, EDDL
EDDS, EDDH
EDDK, EDDH

My problem is now, that I just want one of the rows, IF the data exist in the correlation “EDDH – EDDK” AND “EDDK – EDDH”.

The query for this result is something like this:

SELECT DISTINCT p.depicao, p.arricao FROM xyz WHERE xxyyzz = 1

Thanks for your help!

Answer

Order the columns in a consistent way with GREATEST and LEAST, then use SELECT DISTINCT to remove duplicates.

SELECT DISTINCT GREATEST(depicao, arricao) as col1, LEAST(depicao, arricao) AS col2
FROM xyz
WHERE ...