How to get distinct combination of three columns regardless of order?-CodePudding

I have a table (tablename) with three columns:

c1	c2	c3
A	B	C
A	C	B
A	B	D

I want the output as:

c1	c2	c3
A	B	C
A	B	D

That is, I want the unique combination of values from three columns regardless of which column they are in

Note: The above values are just as an example. My table contains many order combinations

CodePudding user response：

You could convert the columns to an array, sort it, take out the elements, and then use DISTINCT.

SELECT DISTINCT
  c_array[0] AS c1,
  c_array[1] AS c2,
  c_array[2] AS c3
FROM
(
  SELECT sort_array(array(c1, c2, c3)) AS c_array FROM tablename
)
  collapsed

CodePudding user response：

select * from tblname where c1='A' and c2='B'

you can get the output as mentioned above by using this where condition