问题
I want create a visual timeline of all company events. The HTML for the timeline is built using a loop.
For simplicity let's assume two models Hire & Deal. Both models have a date attribute and some model specific attributes. How do I merge the ActiveRecord results of both models, and then order the combined hash by date, into a single hash that I can loop through?
回答1:
Well, assuming that the result of querying both Hire and Deal models is an array of objects (collection), then you just use + to concatenate them into a new array and sort items by date with sort_by:
combined = ( Hire.all + Deal.all ).sort_by(&:date)
or use concat to concatenate one collection with another:
combined = Hire.all.concat( Deal.all ).sort_by(&:date)
来源：https://stackoverflow.com/questions/36094710/combining-two-different-activerecord-collections-into-one