Get the earliest record in a table for each patient

Posted on 2011-02-16
Last Modified: 2012-05-11
Aloha I need to grab the earliest visit of a patient when they were flagged as a smoker.

the fields I have are MRN, Contact_Date and Status. I am having a brain cramp at the moment and drawing a blank. :-) mahalo

Question by:Wonderwall
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LVL 75

Expert Comment

by:Aneesh Retnakaran
ID: 34912716
select mrn, max(contact_date) contactDate
from tableName
where status ='smoker'
group by mrn

Author Comment

ID: 34912795
Sorry, forgot to add I need the status returned also so I can't use the group by  
LVL 75

Expert Comment

by:Aneesh Retnakaran
ID: 34912856
Not sure why you said that

select mrn, max(contact_date) contactDate ,status ='smoker'
from tableName
where status ='smoker'
group by mrn


;with cte as (
select mrn, contact_date, status, rn = row_number() over (partition by status order by contact_date desc )
from tableName
select  mrn, contact_date, status from cte where rn = 1
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LVL 41

Expert Comment

ID: 34912894
select *
  from (
select *,row_number() over (partition by mrn order by contact_date desc) rn
  from your_table
 where status = 'smoker') t1
 where rn = 1

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LVL 55

Accepted Solution

Huseyin KAHRAMAN earned 500 total points
ID: 34913091
I guess "earliest date" means we need to order by ASC
select * from (
select t.*, row_number() over (partition by mrn order by contact_date ASC) rn
  from your_table
 where Smoker = 'Y') x
 where rn = 1

Open in new window

LVL 50

Expert Comment

ID: 34915443
how do we know they are a smoker?

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