SQL: Need to get MAX values from one table and divide by the total number of rows in another table -

-

i have table bunch of scores lessons, on user user basis

------------------------ |uid |lesson_id |score | ------------------------ |1   |0         |20    | |1   |0         |25    | |1   |0         |15    | |1   |0         |40    | |1   |1         |70    | |1   |0         |10    | |1   |1         |20    | |1   |1         |55    | |1   |1         |55    | |1   |0         |5     | |1   |2         |65    | ------------------------

i have table of possible lessons can scored:

------------ |lesson_id | ------------ |0         | |1         | |2         | |3         | |4         | |5         | ------------

i need calculate maximum score each lesson in second table scores in first table, , take average of on number of lessons in second table:

so, maximum scores scores table (for user 1):

----------------------- |lesson_id |max_score | ----------------------- |0         |40        | |1         |70        | |2         |65        | -----------------------

i need sum them: 175 , divide total number of lessons in table 2: 6 should give answer 29.16

any ideas how in single statement?

i can average of max values scores table (for user 1) so:

select avg(max_score) avg_max_score  (     select uid, lesson_id, max(score) max_score cdu_user_progress      , uid =1     group lesson_id  ) m 

select     avg(max_score)    (      select          lesson.lesson_id,          max(isnull(score,0)) max_score              lesson     left join          cdu_user_progress     on          lesson.lesson_id = cdu_user_progress.lesson_id     group          lesson.lesson_id    ) m

Comments

Post a Comment

Popular posts from this blog

python - Subclassed QStyledItemDelegate ignores Stylesheet -

-
i'm trying subclass qstyleditemdelegate remove focus rectangle in qcombobox . even though i'm calling base implementation of paint function , nothing else, result different. looks if parts of style-sheet influence bounding box of item taken consideration. class pstyleditemdelegate(qstyleditemdelegate): def __init__(self, *args, **kwds): super(pstyleditemdelegate, self).__init__(*args, **kwds) def paint(self, *args, **kwargs): qstyleditemdelegate.paint(*args, **kwargs) what have paint unmodified qstyleditemdelegate ? as suggested tried replacing pyside pyqt4 , works, appears bug. update pyside 1.1.2 1.2.1 result same. unfortunately switch breaks other parts of code, if there no other suggestions i'm going accept answer. edit bug tracked here
Read more

java - HttpClient 3.1 Connection pooling vs HttpClient 4.3.2 -

-
i have used httpclient3.1(java) connection pooling below : import org.apache.commons.httpclient.httpclient; import org.apache.commons.httpclient.multithreadedhttpconnectionmanager; import org.apache.commons.httpclient.params.httpclientparams; import org.apache.commons.httpclient.params.httpmethodparams; import org.apache.log4j.logger; public class httpclientmanager { private static logger logger = logger.getlogger(httpclientmanager.class); private static multithreadedhttpconnectionmanager connectionmanager = new multithreadedhttpconnectionmanager(); private static httpclientparams clientparams = new httpclientparams(); static { try { clientparams.makelenient(); clientparams.setauthenticationpreemptive(false); clientparams.setparameter(httpmethodparams.so_timeout, new integer(30000)); // set so_timeout clientparams.setparameter(httpmethodparams.head_body_check_timeout, new integer(3000)); // head responses ...
Read more

node.js - StackOverflow API not returning JSON -

-
i using node.js script gather data stackoverflow. know responses gzipped, put code in should take care of that. script follows: var request = require('request'); var zlib = require('zlib'); function getstackoverflowresponse(url, callback){ request(url, {encoding: null}, function(err, response, body){ if(response.headers['content-encoding'] == 'gzip'){ zlib.gunzip(body, function(err, dezipped) { callback(dezipped); }); } else { callback(body); } }); } var url = "https://api.stackexchange.com/docs/questions#pagesize=2&order=desc&min=2014-01-04&max=2014-02-02&sort=activity&tagged=apigee&filter=default&site=stackoverflow&run=true"; getstackoverflowresponse(url, function(questions) { console.log(questions); }); instead of getting json output, i'm getting following response: buffer 0d 0a 0d 0a 0d 0a 0d 0a 3c 21 44 4f 43 54 59 50 45 20 48...
Read more