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
545 views
in Technique[技术] by (71.8m points)

ruby on rails - How can I count the number of records that have a unique value in a particular field in ROR?

I have a record set that includes a date field, and want to determine how many unique dates are represented in the record set.

Something like:

Record.find(:all).date.unique.count 

but of course, that doesn't seem to work.

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)

This has changed slightly in rails 4 and above :distinct => true is now deprecated. Use:

Record.distinct.count('date')

Or if you want the date and the number:

Record.group(:date).distinct.count(:date)

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

1.4m articles

1.4m replys

5 comments

57.0k users

...