Question

我正在尝试通过Rails生成这个SQL语句：

SELECT * FROM reward_cards
INNER JOIN reward_card_payments 
  ON reward_card_payments.reward_card_id = reward_cards.id
INNER JOIN payments 
  ON payments.id = reward_card_payments.payment_id AND payments.amount < 0;

是否存在类似于此的'rails'方式：

RewardsCard.joins(reward_card_payments => {:payments => payments.amount < 0})

Answer 1

我能找到的最佳方式是

RewardsCard.joins(:reward_card_payments).joins(
  'INNER JOIN payments 
    ON payments.id = reward_card_payments.payment_id AND payments.amount < 0'
)

在Rails中，如何进行复杂的嵌套连接

1 个答案: