求助大神，求助大神
. use match_phone.dta,clear
. merge 1:m phone using customs`i'.dta
file customs.dta not found
r(601);
. forvalue i=1/12{
  2. merge 1:m phone using customs`i'.dta
  3. keep if _m=3
  4. drop _merge  
  5. gen match_method_match_`i'="phone"  
  6. gen match_status_match_`i'="3"  
  7. compress  
  8. save matched_by_phone`i'.dta,replace
  9. }
(note: variable telephone was str11, now str20 to accommodate using data's values)
    Result                           # of obs.
    -----------------------------------------
    not matched                     1,336,189
        from master                   228,325  (_merge==1)
        from using                  1,107,864  (_merge==2)
    matched                           225,295  (_merge==3)
    -----------------------------------------
=exp not allowed
r(101);
. keep if _merge=3
=exp not allowed
r(101);