********
input year country gdp
2007 1 50
2007 2 55
2007 3 54
end
save "D:\year1.dta"
**
input year country gdp
2008 1 77
2008 2 85
2008 3 28
end
save "D:\year2.dta"
**
input year country gdp
2009 1 45
2009 2 87
2009 3 78
end
save "D:\year3.dta"
**
以上假设您的资料,然后在电脑里已存成三年的一年一个档
***************
append using "D:\year1.dta" "D:\year2.dta" "D:\year3.dta"
*就得到您想要的,
*如果还觉得不顺眼,
sort country year
order country
*就是您要的