Question

我有两个型号

客户和交易

 Customer
     has_many :transactions

 Transaction
     belongs_to :customer

现在我需要所有拥有

的客户

过去30天内超过1笔交易
过去30天内完成了1笔交易

Answer 1

扩展ScottJShea的答案，我会使用一些范围

 scope :one_recent_transaction, :conditions => lambda {
   includes(:transactions).where("transactions.date > ?", DateTime.now - 30.days).group("customer.id").having("COUNT(transactions.id) = 1")
 }

 scope :many_recent_transactions, :conditions => lambda {
   includes(:transactions).where("transactions.date > ?", DateTime.now - 30.days).group("customer.id").having("COUNT(transactions.id) > 1")
 }

然后像这样使用它们

one_transaction = Customer.one_recent_transaction
many_transactions = Customer.many_recent_transactions

Answer 2

您想使用HAVING子句。我建议（我猜测有点不完全了解你的模型）：

@exactly_one = Customer.where("transaction_date between ? and >", Date.now, Date.now - 30).group("customer.id").having("count(transaction.id) = 1")

@exactly_one = Customer.where("transaction_date between ? and >", Date.now, Date.now - 30).group("customer.id").having("count(transaction.id) > 1")

需要帮助来理解rails活动记录查询

2 个答案: