错误：被零除+ PostgrSQL + Rails

Question

我在psql中运行此数据库视图时收到以下错误（错误：被零除）。甚至我都无法在Rails控制台中访问我的表。如果有人对此错误有任何解决方案，请对此发表评论，谢谢。

select 
      (exam_id || '00' || quarter)::bigint as id,
      account_id,
      exam_id,
      quarter,
      quarter_label,
      count(id) as assessments,
      max(banding_percentage) as top_assessment_percentage,
      min(banding_percentage) as bottom_assessment_percentage,
      round(avg(banding_percentage),2) as avg_assessment_percentage
    from report_assessments
    group by account_id, exam_id, quarter, quarter_label;

Answer 1

为了避免遇到division by zero异常，您应该使用nullif，以便可以捕获此nullif并将其替换为0，例如

null

Answer 2

您需要做这样的事情。在我的情况下有效：

WITH j (v1,v2) AS (
  VALUES (1.0,0.0),(10.0,3.0)
) 
SELECT v1/nullif(v2,0) AS div FROM j;

        div         
--------------------

 3.3333333333333333
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