Question

现在我正在通过Dealings.all获取交易信息，并执行以下拒绝语句，但是有一种方法可以让我一口气查询它吗？我有一些ruby代码，例如pluck和max，我想知道是否可以在SQL代码中混合使用ruby代码。

dealings.reject {| n |

（n.item_rank ==：import && n.dealings.pluck（：status）.max == Contract :: import）||       （n.item_rank ==：process && n.dealings.pluck（：status）.max == Contract :: process）||       （n.item_rank ==：export && n.dealings.pluck（：status）.max == Contract :: export）     }

结束

Answer 1

我相信使用子查询是可能的。这是原始的sql示例：

negotiations = Negotiation.from('(select negotiations.*, (select max(status) from deal_buildings where deal_buildings.deal_id = negotiations.id) max_status from negotiations) negotiations')
negotiations = negotiations.where(business_rank: [17, 19, 22])
negotiations = negotiations.where(main_member_id: 7)
negotiations = negotiations.where(
  '((business_rank = ? and max_status = ?) or (business_rank = ? and max_status = ?) or (business_rank = ? and max_status = ?)) is false',
  'application', Supplier::Building::STATUS_APPLY,
  'agreement', Supplier::Building::STATUS_CONTRACT,
  'settlement', Supplier::Building::STATUS_SETTLEMENT
)

还有query object：

class NegotiationsQuery
  def all
    Negotiation.from(negotiations_and_max_status_query)
  end

  private

  def negotiations
    @negotiations ||= Arel::Table.new(:negotiations)
  end

  def deal_buildings
    @deal_buildings ||= Arel::Table.new(:deal_buildings)
  end

  def max_status_query
    deal_buildings.project(deal_buildings[:status].maximum).where(
      deal_buildings[:deal_id].eq(negotiations[:id])
    ).as('max_status')
  end

  def negotiations_and_max_status_query
    negotiations.project(negotiations[Arel.star], max_status_query).as('negotiations')
  end
end

  negotiations = NegotiationsQuery.new.all
  negotiations = negotiations.where(business_rank: [17, 19, 22])
  negotiations = negotiations.where(main_member_id: 7)
  negotiations = negotiations.where(
    '((business_rank = ? and max_status = ?) or (business_rank = ? and max_status = ?) or (business_rank = ? and max_status = ?)) is false',
    'application', Supplier::Building::STATUS_APPLY,
    'agreement', Supplier::Building::STATUS_CONTRACT,
    'settlement', Supplier::Building::STATUS_SETTLEMENT
  )

是否可以将此拒绝转换为有效记录查询？

1 个答案: