sas 如何删除无连续三年值的样本

删除无连续三年值的样本——sas 命令，劳烦高手指点，谢谢！

1. /*示例数据集*/
   
2. data have;
   
3. input year value;
   
4. cards;
   
5. 2000  1
   
6. 2000  2
   
7. 2000  3
   
8. 2001  1
   
9. 2001 2
   
10. 2002 1
    
11. ;
    
12. /*data step*/
    
13. proc sort data=have;
    
14. by year;
    
15. run;
    
16. data result(drop=cnt);
    
17. do _n_=1 by 1 until(last.year);
    
18. set have;
    
19. by year;
    
20. if last.year then cnt=_n_;
    
21. end;
    
22. do _n_=1 to _n_;
    
23. set have;
    
24. if cnt=3 then output;
    
25. end;
    
26. run;
    
27. /*SQL*/
    
28. proc sql;
    
29. create table result2 as
    
30. select * from have
    
31. group by year
    
32. having(count(*)=3);
    
33. quit;

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