Question

Lets assume i have a table called VISITS containing the following

• VISIT_DATE (TIMESTAMP)
• HEIGHT (NUMBER)
• WAIST (NUMBER)
• WEIGHT(NUMBER)

• PATIENT_ID (NUMBER)

  VISIT_DATE| HEIGHT | WAIST | WEIGHT | PATIENT_ID

  10/01/2012 | (null)      | 96      | 130 | 44123

  11/01/2012 | 1.74       | (null)  | 120 | 44123

  12/01/2012 | (null)      | (null)  | 150 | 44123

What I need is a sql select statement to get the most recent value for each column but ignoring the null fields so the output I need would be

The WHERE clause would be

WHERE PATIENT_ID = 44123 ORDER BY VISIT_DATE DESC LIMIT 1

---

12/01/2012 | 1.74 | 96 | 150 | 44123

As you can see from the output I expect to get from the select I am stepping backwards through each row for the patient until I find a value for each field.

I hope this question is clear and possible, I have searched but haven’t found any real solution up to now, this is going to be used to streamline a medical system being used with hospitals and there is about 100 fields the above is just an example of a few fields to get the concept across of what is required.

Answer 1

create table VISITS 
(
  VISIT_DATE TIMESTAMP
, HEIGHT NUMBER
, WAIST NUMBER
, WEIGHT NUMBER
, PATIENT_ID NUMBER
);


insert into visits values(systimestamp, null, 96, 130, 44123);
insert into visits values(systimestamp, 1.74, NULL, 120, 44123);
insert into visits values(systimestamp, null, NULL, 150, 44123);




select 
  last_visit_date
, height
, waist
, weight
, patient_id
from
(
  select 
    first_value( VISIT_DATE) over( partition by patient_id order by visit_date desc) last_visit_date
  , first_value( HEIGHT ignore nulls) over( partition by patient_id order by visit_date desc) height
  , first_value( WAIST ignore nulls) over( partition by patient_id order by visit_date desc) WAIST
  , first_value( WEIGHT ignore nulls) over( partition by patient_id order by visit_date desc) WEIGHT
  , min(visit_date) over( partition by patient_id)  min_visit_date
  , visit_date
  , patient_id
  from visits

)
where 
  min_visit_date = visit_date
and patient_id = 44123
;

Here is SQLfiddle example