st: Re: merging without repeat obs in master dataset

["Michael Blasnik" <michael.blasnik@verizon.net>]

...

Your first statement is incorrect -- merge does not require a unique key unless 
you tell it that's what you expect/want/require.
Just omit the -sort- option to your merge command and it will work.  The help 
for -merge- notes that -sort- implies that the key is unique in both datasets.

M Blasnik

----- Original Message ----- 
From: "Mingfeng Lin" <mingfeng.lin@gmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Thursday, May 22, 2008 10:51 PM
Subject: st: merging without repeat obs in master dataset



> Greetings!
>
> The -merge- command in Stata requires that the variable to merge
> uniquely identify observations in the master dataset.  But how should
> I merge if the variable I would like to merge on does not uniquely
> identify master dataset observations?
>
> For instance:
> Master: ID GROUP
> (multiple IDs could be in the same group)
>
> Using dataset:   GROUP GROUPDEMOGRAPHICS
>
> I wanted to do
> .merge GROUP using ..., sort
>
> error message r(459):  something that should be true of your data is not;
>
> My final dataset should have each ID as an observation. Is there
> something I can do to work around this?
>
> Thank you!
>
> Mingfeng
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