python - SQLAlchemy: filter on operator in a many-to-many relationship -

-

i have 2 classes many-to-many relationship, items , categories.

categories have associated value.

i query items highest categorie.value (if there any) less given value.

so far have tried queries this:

from sqlalchemy.sql import functions  session.query(items).join(categories,items.categories).filter(functions.max(categories.value)<3.14).all()

but in case (operationalerror) misuse of aggregate function max() error.

is there way make query?

you need group by , having instead of where filtering on aggregate.

session.query(items).join(items.categories).group_by(items.id).having(functions.max(categories.value)<3.14).all()

edit: include items without category, believe can outer join , put or in having clause:

session.query(items).outerjoin(items.categories).group_by(items.id)\ .having( (functions.max(categories.value)<3.14) | (functions.count(categories.id)==0) )\ .all()

Comments

Post a Comment

Popular posts from this blog

python - mat is not a numerical tuple : openCV error -

-
i have write down code showing error ma not getting it: please help: showing mat not numerical tuple: import cv import cv2 capture = cv2.videocapture("j.3gp") while(1): _, frame1 = capture.read() grayimage1 = cv2.cvtcolor(frame1, cv2.color_bgr2gray) _, frame2 = capture.read() grayimage2 = cv2.cvtcolor(frame2, cv2.color_bgr2gray) differenceimage = cv2.absdiff(grayimage1,grayimage2) thresholdimage = cv2.threshold(differenceimage,25,255,cv2.thresh_binary) cv2.imshow("difference image", differenceimage) cv2.imshow("threshold image", thresholdimage) cv2.imshow("image", frame1) k = cv2.waitkey(30) & 0xff error arising : ----------------------------------------------------------------------------------------- traceback (most recent call last): file "desk.py", line 15, in <module> cv2.imshow("threshold image", thresholdimage) typeerror: mat not numerical tuple ...
Read more

c# - MSAA finds controls UI Automation doesn't -

-
i'm working on automating windows application. i'm using teststack white framework. i've hit problem. program has 'window' object cannot see inside of. white shows no controls inside of it. inspect.exe shows no controls inside of either when running in ui automation mode. if switch inspect msaa see controls inside fine. there anyway me use msaa c# handle on these controls? if can identify msaa functions need, can use p/invoke call them c#. here's example article doing msaa: http://www.codeproject.com/articles/38906/ui-automation-using-microsoft-active-accessibility also, pinvoke.net can used identify iaccessible (msaa) functions: http://www.pinvoke.net/search.aspx?search=iaccessible&namespace=[all] here's answer along lines: msaa com-based? finally, alternative p/invoke, might able use tlbimp.exe create wrapper assembly oleacc.dll, , access msaa functions through it. i'm not sure if works msaa, it's worth try. as e...
Read more

wordpress - .htaccess: RewriteRule: bad flag delimiters -

-
pulling hair out on one. have following .htaccess file custom redirects in addition wordpress's default settings. when tested on local wamp server worked fine after moving production i'm not getting rewriterule: bad flag delimiters error in server log , after while site goes down internal server error any appreciated. in advance! <ifmodule mod_rewrite.c> rewriteengine on rewritebase / rewriterule ^rockford_weddings___welcome\.html$ /wedding/ [r=301,l] rewriterule ^blog/?$ /journal/ [r=301,l] rewriterule ^blog/(.*)$ /$1 [r=301,l] rewriterule ^portraitinvestment/?$ /portraitinvestment\.pdf [r=301,l] rewriterule ^weddinginvestment/?$ /weddinginvestment\.pdf [r=301,l] rewriterule ^holidaycards2014/?$ /holidaycards2014\.pdf [r=301,l] </ifmodule> # begin wordpress <ifmodule mod_rewrite.c> rewriteengine on rewritebase / rewriterule ^index\.php$ - [l] rewritecond %{request_filename} !-f rewritecond %{request_filename} !-d rewriterule . /index.php [l] </...
Read more