--SQL Interview question --Find out the possible pair but the pair should not repeat with respect to the order of the pair  --Table has 5 rows maximum possible pair is 10 CREATE TABLE COUNTRY (Country_name nvarchar(100)) insert into COUNTRY values ('INDIA'),('US'),('UK'),('Oman'),('Russia') SELECT REPLICATE ('*',500) As 'INPUT TABLE' GO select * from COUNTRY GO SELECT REPLICATE ('*',500) As 'OUTPUT TABLE' go  WITH COUNTRY_1 AS ( SELECT ROW_NUMBER () OVER (ORDER BY Country_name DESC ) as'Country_ID',* FROM COUNTRY ) SELECT CONCAT(C1.Country_name,'-',C2.Country_name) as 'PAIR_NAME' FROM COUNTRY_1  C1 INNER JOIN  COUNTRY_1 C2 ON C1.Country_ID > C2.Country_ID