How to make a Cartesian product, by group, of character observations

[KS99]

Hi, greetings,

If anyone can help me with this, I will greatly appreciate it.  

Suppose I have the following dataset, 

data HAVE; 
input  ID  year $ country;
cards;
1  2000 USA
1  2000 ESP
2  2004 GBR
2  2004 USA
2  2004 NLD
2  2005 USA
2  2005 DEU
2  2005 ISR
2  2005 CHE

;
run; 

I want to create a new dataset that looks like below, 

__________________________

ID  year country1 country2;
1  2000 USA ESP 

2  2004 GBR USA 
2  2004 USA NLD 
2  2004 NLD GBR 

2  2005 USA DEU
2  2005 USA ISR 
2  2005 USA CHE 
2  2005 DEU ISR

2 2005 DEU CHE
2 2005 ISR CHE

.....

....

...
________________________ 

In other words, I want to form a every possible (Cartesian) pair-product of countries, by ID and year, without duplicates (for example, DEU-CHE and  CHE-DEU are the same, therefore only one of the two are entered). 

Many times I obtain a great help from SAS communities, and 

if you can help me one more time this time, I will be more than thankful to you guys. 

Have a wonderful day! 

KS -, 

[Reeza]

CROSS JOIN with year and ensure that one side is greater than the other side to avoid duplicates.

[KS99]

But they are character variables. How can I determine one side is quantitatively greater than the other side?  

[Reeza]

Try the suggestion. Alphabetical order for characters will work as expected.

[KS99]

Oh really? Thank you !! 

[KS99]

I am such a Newbie in SAS.. 

Can you provide a clue code to achieve this? 

Many thanks! 

KS -, 

[Sajid01 · Accepted solution]

From your requirement you want combination of countries by year and ID and no duplicates.
From the required output given in your question you want all combination of countries.
While there are many approaches to the solution, with the understanding I have of your requirements, I suggest the following code.
This is an example try modifications / improvements as needed.

data HAVE; 
input  ID  year  country $;
cards;
1  2000 USA
1  2000 ESP
2  2004 GBR
2  2004 USA
2  2004 NLD
2  2005 USA
2  2005 DEU
2  2005 ISR
2  2005 CHE

;
run; 
proc sql;
create table want as
select a.* , b.country as country2 from have  a cross join have  b
where a.country ne b.country
order by id, year, country;
run;

[ChrisNZ]

where a.country gt b.country

[KS99]

Thank you ChrisNZ ! 

Your code was producing Cartesian productions of all countries against all countries; 

But it gave me a clue how to do it. 

I separated two datasets, and using a chain of where (a.ID=b.ID and a.year=b.year and a.country gt b.country1), 

obtained my wished-for results.