Distinct pair of values SQL

Question

Consider   create table pairs   number a  number b      Where the data is   1 1 1 1 1 1 2 4 2 4 3 2 3 2 5 1   Etc    What query gives me the distinct values the number column b has So I can see  1 1 5 1 2 4 3 2   only   I ve tried  select distinct   a     b from pairs group by b    but gives me  not a group by expression

User · Answer

This will give you the result you re giving as an example   SELECT DISTINCT a  b FROM pairs

User · Answer

What you mean is either  SELECT DISTINCT a  b FROM pairs    or  SELECT a  b FROM pairs GROUP BY a  b

User · Answer

If you want to want to treat  1 2 and 2 1 as the same pair  then this will give you the unique list on MS-SQL   SELECT DISTINCT      CASE WHEN a  gt  b THEN a ELSE b END as a      CASE WHEN a  gt  b THEN b ELSE a END as b FROM pairs   Inspired by  meszias answer above

User · Answer

if you want to filter the tuples you can use on this way   select distinct  case a  gt  b then  a b  else  b a  end  from pairs   the good stuff is you don t have to use group by

User · Answer

If you just want a count of the distinct pairs   The simplest way to do that is as follows SELECT COUNT DISTINCT a b  FROM pairs  The previous solutions would list all the pairs and then you d have to do a second query to count them

[sql] Distinct pair of values SQL

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