如何使用ActiveRecord采集相关数据?rails pluck has_many through count
我想有两列返回,PatientProfile.name
和PatientProfile.recommendations.length
我试着用下面这个answer
class PatientProfile
has_many :recommendations
PatientProfile.joins(:recommendations).select("patient_profiles.name as name, count(recommendation.id) as rec_count")
'计数(recommendation.id)'应'count(recommendations.id)''除非你将'推荐'模型的数据库表覆盖到'推荐' –
@MichaelGorman这不适合我。我错过了什么吗? – user2954587