如何处理带有“ not in”的where子句和具有活动记录的子查询

Question

我该如何用activerecord（ruby on rails）编写这样的子查询：

SELECT id, unit_cdl_required, load_group_id
FROM loads lo
WHERE unit_cdl_required=FALSE AND
load_group_id NOT IN (
  SELECT load_group_id
  FROM loads
  WHERE unit_cdl_required=TRUE
  AND load_group_id=lo.load_group_id
);

我尝试过：

Load.where("unit_cdl_required=FALSE AND load_group_id NOT IN (SELECT load_group_id FROM loads WHERE unit_cdl_required=TRUE AND load_group_id=lo.load_group_id)")

但是得到了ERROR: missing FROM-clause entry for table "lo"

我的模式是这样的：https://imgur.com/a/wr9Yzl2

Answer 1

您有一个奇怪的内置sql查询，也许您想做这样的事情：