c# - Finding Average of value based on count of rows in LINQ -


i have restaurant review application has separate restaurant , reviews table. have built mvc webapi has method passes restaurant object based on id of restaurant.

as part of object returned add average rating value, based on sum of rating values entered on reviews table divided restaurant id total count of reviews entered restaurant id.

it great if value in 1 decimal place format.

i able average value(no decimal places) reviews table using following code

var sum = (from in db.reviews            a.reviewsrestaurantid.equals(id)            select a.reviewsrating).sum();  var count = (from in db.reviews              a.reviewsrestaurantid.equals(id)              select a.reviewsrating).count();  decimal average = sum / count;

i not sure how can add value query used return restaurant id method (pls see below). can please in adding custom average rating value method below or there way join on reviews table , calculate value more efficiently? 

public iqueryable<restaurant> getrestaurantbyid(int id) {    var query = in db.restaurants               a.restaurantid.equals(id)               select a;    return query;  }

for starters, can pare down code + traffic server. since mentioned tables, rows, , db, guess going sql server.

start getting of stuff care server, i.e.

var reviews = (from x in db.reviews a.reviewsrestaurantid.equals(id) select x).tolist();

now don't have make 2 seperate trips server collect data care about. can run , 'average' query on data have in memory...

// assuming, sample ratings stored decimals.... // counting, summing, dividing, etc. decimal avg = (from x in reviews select x.rating).average();

Comments

Post a Comment

Popular posts from this blog

basic authentication with http post params android -

i doing basic authentication passing username , password , using basicnamevaluepair sending post params response service. my method: public stringbuilder callservicehttppost(string username, string password, string type) { // create new httpclient , post header httpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(webservice + type); httpresponse response = null; stringbuilder total = new stringbuilder(); try { url url = new url(webservice + type); /*string base64encodedcredentials = base64.encodetostring((username + ":" + password).getbytes(), base64.url_safe | base64.no_wrap);*/ string base64encodedcredentials = "basic " + base64.encodetostring( (username + ":" + password).getbytes(), base64.no_wrap); httppost.setheader("auth...
Read more

vb.net - Virtual Keyboard commands -

i wondering difference between virtual these keyboard commands is: keyeventf_extendedkey , keyeventf_keyup is. everywhere have looked gives me description based off integers , not want know each of them does. you've tagged question vb.net, these have nothing @ vb.net. they're constants defined in windows header files, use win32 api functions. as far difference, can't tell looking @ values. individual values not particularly important, that's why named identifiers used. what's important used , documentation functions tells mean. the first one, keyeventf_extendedkey , used keybdinput structure (which used along e.g. sendinput function) pass information synthesized keyboard input. if flag used, means scan code should interpreted extended key. technically, means scan code preceded prefix byte value 224 (&he0 in hexadecimal notation). the second one, keyeventf_keyup , 1 of flags available use structure. means key being released (going up)...
Read more

How to get multiresult with multicondition in Sql Server -

i need solve this. hopefully can giving me advices. for sample, i've got data : proclib.march 1 first 10 rows flight date depart orig dest miles boarded capacity ----------------------------------------------------------------- 114 01mar94 7:10 lga lax 2475 172 210 202 01mar94 10:43 lga ord 740 151 210 219 01mar94 9:31 lga lon 3442 198 250 622 01mar94 12:19 lga fra 3857 207 250 132 01mar94 15:35 lga yyz 366 115 178 271 01mar94 13:17 lga par 3635 138 250 302 01mar94 20:22 lga 229 105 180 114 02mar94 7:10 lga lax 2475 119 210 202 02mar94 10:43 lga ord 740 120 210 219 02mar94 9:31 lga lon 344...
Read more