Laravel-如何对模型之间的关系求和（即不在记录级别上进行记录）

Question

性能优化

出于性能原因，我不想用雄辩的语言来产生一个集合。我宁愿让SQL承担繁重的工作，并计算所有符合特定条件的索赔中签署的授权书总数，以避免在每个索赔记录中循环生成PHP（例如，通过withCount等）

我想做些简单的事情：

Claim::join('powers_of_attorney', 'powers_of_attorney.claim_id', '=', 'claims.id')->selectRaw(['claims.id', 'count(case when powers_of_attorney.status = "closed" and powers_of_attorney.claim_id = claims.id and powers_of_attorney.deleted_at is null then powers_of_attorney.id end) as poasSigned'])->sum('poasSigned');

应根据以下条件工作： Laravel Query Builder - Use sum method on a generated attribute

但是我收到错误消息

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'poasSigned' in 'field list' (SQL: select sum(`poasSigned`) as aggregate from `claims` inner join `powers_of_attorney` on `powers_of_attorney`.`claim_id` = `claims`.`id` where `claims`.`deleted_at` is null)

关于如何解决的想法？

索赔模型

id
name
...

授权书模型

id
claim_id
status
...