Help with SQL Syntax
Hoping someone can help with a photo gallery migration...I'm not really proficient with SQL, but am 99% done.
I have two tables, PHOTOS and PHOTOS_ALBUMS
PHOTOS is essentially all the pictures in the gallery (id), along with id of the uploader (creator), and what Album those pictures belong to (albumid).
ALBUMS is all the albums (id), the user that created it (creator), and what Photo should be set as the thumbnail for the album (photoid)
I want to set the thumbnail for all the albums. Some users have multiple albums. I want the thumbnail to be the last photo they uploaded to each album.
So I need a query that will
A) Go through PHOTOS and select the last id from each albumid
B) In ALBUMS set photoid for each album to the last id selected above
Here are some sample tables:
PHOTOS
ID = 1
ALBUMID = 26
CREATOR = 9647
FILE: imagepath/81729.jpg
ID = 2
ALBUMID = 26
CREATOR = 9647
FILE: imagepath/0458435.jpg
ID = 3
ALBUMID = 35
CREATOR = 9647
FILE: imagepath/7347328974.jpg
ALBUMS
ID = 26
CREATOR = 9647
PHOTOID =
So in the example above, I'd want to populate alumbs.photoid with the last photos.id (in this case, 2). Of course I have 100,000 users and 250,000 albums to do this for.
I know I could be clearer, but it's 3:30 AM here and my mind is fried...even I can barely make sense of what I am writing at this hour!
I have two tables, PHOTOS and PHOTOS_ALBUMS
PHOTOS is essentially all the pictures in the gallery (id), along with id of the uploader (creator), and what Album those pictures belong to (albumid).
ALBUMS is all the albums (id), the user that created it (creator), and what Photo should be set as the thumbnail for the album (photoid)
I want to set the thumbnail for all the albums. Some users have multiple albums. I want the thumbnail to be the last photo they uploaded to each album.
So I need a query that will
A) Go through PHOTOS and select the last id from each albumid
B) In ALBUMS set photoid for each album to the last id selected above
Here are some sample tables:
PHOTOS
ID = 1
ALBUMID = 26
CREATOR = 9647
FILE: imagepath/81729.jpg
ID = 2
ALBUMID = 26
CREATOR = 9647
FILE: imagepath/0458435.jpg
ID = 3
ALBUMID = 35
CREATOR = 9647
FILE: imagepath/7347328974.jpg
ALBUMS
ID = 26
CREATOR = 9647
PHOTOID =
So in the example above, I'd want to populate alumbs.photoid with the last photos.id (in this case, 2). Of course I have 100,000 users and 250,000 albums to do this for.
I know I could be clearer, but it's 3:30 AM here and my mind is fried...even I can barely make sense of what I am writing at this hour!
a) SELEXT MAX(ID) FROM ALBUMS GROUP BY ALBUMID
@brandscape: rovermedia wants to update all the albums with the last uploaded photo ID not just select em.
I would suggest using an update based on a select using table alises, something like this
update albums
set albums.photoid = max(sel.id)
from photos sel
group by sel.albumid
where albums.albumid = sel.albumid
update albums
set albums.photoid = max(sel.id)
from photos sel
group by sel.albumid
where albums.albumid = sel.albumid
sorry - my first post was to answer part A) but should read :
a) SELEXT MAX(ID) FROM PHOTOS GROUP BY ALBUMID
IT's usefull to see the answer to B) in context of the answer to A)
a) SELEXT MAX(ID) FROM PHOTOS GROUP BY ALBUMID
IT's usefull to see the answer to B) in context of the answer to A)
SELECT MAX(ID) FROM PHOTOS GROUP BY ALBUMID
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What dbms are you using?
Supposing you work with Microsoft SQL Server, the statement could be :
UPDATE Albums SET PHOTOID = b.maxid from
Albums a INNER JOIN (SELECT AlbumID , Max(ID) maxid FROM Photos group by AlbumID) b
ON a.ID = b.ALBUMID
I could give you a solution in .NET if you want.