Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
235 views
in Technique[技术] by (71.8m points)

c# - linq: order by random

How can I change below code, to each time get 50 different random data from database?

return (from examQ in idb.Exam_Question_Int_Tbl
      where examQ.Exam_Tbl_ID==exam_id
      select examQ).OrderBy(x=>x.Exam_Tbl_ID).Take(50);
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

http://msdn.microsoft.com/en-us/library/system.guid.newguid.aspx

return (from examQ in idb.Exam_Question_Int_Tbl
      where examQ.Exam_Tbl_ID==exam_id
      select examQ).OrderBy(x => Guid.NewGuid()).Take(50);

If this is LINQ-to-SQL you could simply add a ORDER BY NEWID() to your SELECT statement.

As commented it might be better to use an algorithm like Fisher-Yates Shuffle, here is an implementation: https://stackoverflow.com/a/375446/284240


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...