将复杂的postgresql查询/子查询转换为Rails activerecord语法或将数组转换为活动记录关系？

Question

所以我花了很多时间来编写这个查询,然后发现这是一个很难的方式,它返回一个数组而不是一个activerecord关系.DOH.这不会是一个问题,但我需要在这些结果上使用Ransack,这需要关系.

所以,基本上,我需要使用语法.joins()和.select()将其转换为Rails,但我尝试过的所有内容都出错了.我猜我可能需要潜入AREL？

或者,如果这可以很容易地转换为具有最小性能问题的activerecord关系并保留我的别名列,那么它也可以工作!

任何帮助或建议都受到赞赏!

find_by_sql("
  SELECT
    subq.*, 
    renewal_date,
    days_until_due,
    renewal_stage_sort,
    (
      CASE
        WHEN renewal_stage_sort IS NOT NULL THEN
          CASE
            WHEN days_until_due > 42 AND renewal_stage_sort >= 1 THEN TRUE
            WHEN days_until_due > 28 AND days_until_due < 43 AND renewal_stage_sort >= 2 THEN TRUE
            WHEN days_until_due > 13 AND days_until_due < 29 AND renewal_stage_sort >= 3 THEN TRUE
            WHEN days_until_due > -1 AND days_until_due < 14 AND renewal_stage_sort >= 4 THEN TRUE
            WHEN days_until_due < 0 AND renewal_stage_sort >= 5 THEN TRUE
            ELSE FALSE
          END
        ELSE FALSE
      END
    )
    AS on_target
  FROM (   
     SELECT DISTINCT ON (renewals.id) renewals.*,
     CASE
       WHEN renewal_types.name = 'IEP-504' THEN patients.iep_renewal_date
       WHEN renewal_types.name = 'RR' THEN patients.rr_date
       ELSE NULL
     END 
     AS renewal_date,
     (  CASE
          WHEN renewal_types.name = 'IEP-504' THEN patients.iep_renewal_date::date
          WHEN renewal_types.name = 'RR' THEN patients.rr_date::date
          ELSE NULL
        END
        - current_date)
     AS days_until_due, 
     renewal_stages.sort_order AS renewal_stage_sort
     FROM renewals
     INNER JOIN renewal_types ON renewal_types.id = renewals.renewal_type_id
     LEFT JOIN renewal_stages ON renewal_stages.id = renewals.renewal_stage_id
     INNER JOIN patients ON patients.id = renewals.patient_id AND patients.deleted_at IS NULL
     WHERE renewals.deleted_at IS NULL
   ) subq
")    

Answer 1

并没有真正完成全部工作，但这只是一个开始......

http://www.scuttle.io/

给出：

RenewalStages.sortOrder.select(
  [
    Subq.arel_table[Arel.star], :renewal_date, :days_until_due, :renewal_stage_sort, Arel::Nodes::Group.new(
      Arel.sql(
        'CASE        WHEN renewal_stage_sort IS NOT NULL THEN          CASE            WHEN days_until_due > 42 AND renewal_stage_sort >= 1 THEN TRUE            WHEN days_until_due > 28 AND days_until_due < 43 AND renewal_stage_sort >= 2 THEN TRUE            WHEN days_until_due > 13 AND days_until_due < 29 AND renewal_stage_sort >= 3 THEN TRUE            WHEN days_until_due > -1 AND days_until_due < 14 AND renewal_stage_sort >= 4 THEN TRUE            WHEN days_until_due < 0 AND renewal_stage_sort >= 5 THEN TRUE            ELSE FALSE          END        ELSE FALSE      END'
      )
    ).as('on_target')
  ]
).where(Renewal.arel_table[:deleted_at].eq(nil))

是的，显然需要 Arel 表