命令:merge m:1 classid using baseline_clean_teachers.dta, gen(m2)
variable classid does not uniquely identify observations in the using data
可是同样类型的数据库用 merge m:1 schid using baseline_clean_principals.dta, gen(m1)就可以merge
原命令如下:
use baseline_clean_teachers.dta,clear
gen classid=substr(teaid,1,8)
sort classid
save,replace
use baseline_clean_principals.dta,clear
tostring schid,replace
sort schid
save,replace
use baseline_clean_student.dta,clear
sort old_studentid
gen classid=substr(old_studentid,1,8)
gen schid=substr(old_studentid,1,6)
merge m:1 schid using baseline_clean_principals.dta, gen(m1)
merge m:1 classid using baseline_clean_teachers.dta, gen(m2)
此外,之前在第一个merge处,在变量schid为数值型的时候merge会出现merge在底部的情况(有点像append那样),为字符型的时候merge结果就是正常的
stata新手,感谢您的解释!