Nearest to a fixed value

Dev Shed Forums Sponsor:

April 27th, 2007, 06:56 AM

aleplgr

Registered User

Join Date: Mar 2007

Posts: 20

Time spent in forums: 6 h 14 m 41 sec
Reputation Power: 0

Nearest to a fixed value

Hi! I'm trying to solve this:
I have this table
PatientID DateIni Dateend Days

For each PatientID there are many Dateend but only one DateIni.
Days is the difference between Dateend and DateIni.

I need to find for each PatientID the Dateend which Days value is nearest to 365.

So for each PatientID I can have 3 cases:
1.For all the Dateend all the Days value are less than 365 return the greatest Dateend
2. There are Dateend which Days value is less than 365 and other which are greater than 365, return the greatest Dateend that's less than 365
3. All the Dateend have all the Days value greater than 365 return the less Dateend

I could GROUP BY Patientid and if for each PatientID there's at least one Dateend which Days <365 return MAX(Dateend) else return MIN (Dateend)
But I don't know how to loop in each group and how to create the groups..

April 30th, 2007, 03:48 AM

aleplgr

Registered User

Join Date: Mar 2007

Posts: 20

Time spent in forums: 6 h 14 m 41 sec
Reputation Power: 0

Just to tell that it's done!!! This solves the problem:

Code:

select T1.PatientID, T1.DateIni, min(T1.Dateend) , min(T1.Days)
from ThisTable T1
where not exists(select * from ThisTable T2
where T2.PatientID = T1.PatientID
and T2.Days between T1.Days+1 and 365)
group by 1, 2

April 30th, 2007, 12:39 PM

clivew

Contributing User

Join Date: Jan 2006

Location: Carlsbad, CA

Posts: 855

Time spent in forums: 4 Days 11 h 11 m 43 sec
Reputation Power: 19

Quote:

Originally Posted by aleplgr

Just to tell that it's done!!! This solves the problem:

Code:

select T1.PatientID, T1.DateIni, min(T1.Dateend) , min(T1.Days)
from ThisTable T1
where not exists(select * from ThisTable T2
where T2.PatientID = T1.PatientID
and T2.Days between T1.Days+1 and 365)
group by 1, 2

Can you help me understand how?

With a where clause that appears to exclude any patient who has any Days value between 1 and 365
how do you get the first and second group of results?

Quote:

1.For all the Dateend all the Days value are less than 365 return the greatest Dateend
2. There are Dateend which Days value is less than 365
and other which are greater than 365,
return the greatest Dateend that's less than 365

Also, I am curious about what gets returned with two min clauses.
Do you get two records per patient?
min(T1.Dateend) , min(T1.Days)
min(T1.Days),min(T1.Dateend)

or What?

Thanks,
Clive

Viewing: Dev Shed Forums > Databases > Firebird SQL Development > Nearest to a fixed value

« Previous Thread | Next Thread »

Thread Tools	Search this Thread
Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

Posting Rules
You may not post new threads You may not post replies You may not post attachments You may not edit your posts vB code is On Smilies are On [IMG] code is On HTML code is Off

View Your Warnings | New Posts | Latest News | Latest Threads | Shoutbox

Forum Jump