Re: st: merging multiple files in stata

[Steve Nakoneshny <scnakone@ucalgary.ca>]

Negussie,

The trouble with the code you provided is that you did not save your merged dataset prior to loading your "opmnth.dta" file. So while it didn't do what you *wanted* it did do what you *told* it to do.

Here is one possible solution for you, assuming -merge- syntax from Stata 11:
---------------------------------
use "C:\UserFiles\physndata.dta", clear 
compress 
rename pp_mnth mnth
sort bene_id mnth, stable
keep bene_id mnth pp_mnthexp 
tempfile physn
save `physn'

use "C:\UserFiles\hspsdata.dta", clear 
compress 
rename hs_mnth mnth
sort bene_id mnth, stable
keep bene_id mnth hs_mnthexp
tempfile hsps
save `hsps'

use "C:\UserFiles\opmnth.dta", clear 
compress 
rename op_mnth mnth
sort bene_id mnth


merge 1:1 bene_id mnth using `physn'
drop _merge

merge 1:1 bene_id mnth using `hsps'

save "C:\UserFiles\mymergeddata.dta", replace

-------------------------------------------------

Steve

On 2012-03-22, at 8:17 AM, Tilahun, Negussie (CMS/CMMI) wrote:

> Hello!
> 
> I am an experienced sas programmer but I just started to work with stata.
> 
> How can I merge multiple files? I can merge two files successfully but
> merging more than two becomes difficult. 
> The program below run without error but I don't get the result I expected.
> i.e. after I merged the third file, the output file, temp_hsps, doesn't
> contain data from all the three files - it contains data only from the first
> two files.  
> 
> 
> Thanks,
> Negussie 
> 
> 
> Here is my code
> 
> clear all
> set mem 500m
> 
> 
> use "C:\UserFiles\physndata.dta", clear 
> compress 
> rename pp_mnth mnth sort bene_id mnth, stable
> keep bene_id mnth pp_mnthexp save "C:\UserFiles\temp_physn.dta", replace
> 
> use "C:\UserFiles\hspsdata.dta", clear 
> compress 
> rename hs_mnth mnth sort bene_id mnth, stable
> keep bene_id mnth hs_mnthexp save "C:\UserFiles\temp_hsps.dta", replace
> 
> use "C:\UserFiles\temp_physn.dta"
> merge bene_id mnth using "C:\UserFiles\temp_hsps.dta"
> 
> sort bene_id mnth
> drop _merge
> 
> use "C:\UserFiles\opmnth.dta", clear 
> compress 
> rename op_mnth mnth sort bene_id mnth save "C:\UserFiles\temp_opmnth.dta",
> replace
> 
> use "C:\UserFiles\NT\suraphl\temp_opmnth.dta"
> merge bene_id mnth using "C:\UserFiles\temp_hsps.dta" 
> sort bene_id mnth
> drop _merge
> 
> ......
> 


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