Oracle CASE 短路不能按组工作

Question

我在documentation of case statment中发现它使用短路：

Oracle Database uses short-circuit evaluation. That is, for a simple CASE expression, the database evaluates each comparison_expr value only before comparing it to expr, rather than evaluating all comparison_expr values before comparing any of them with expr. Consequently, Oracle never evaluates a comparison_expr if a previous comparison_expr is equal to expr. For a searched CASE expression, the database evaluates each condition to determine whether it is true, and never evaluates a condition if the previous condition was true.

但是下面的 SQL 正在返回 divisor is equal to zero:

WITH data AS (SELECT 1 AS cond, 10 AS num, 0 AS div FROM DUAL)
SELECT
  CASE WHEN cond = 2 THEN (CASE WHEN MAX(div) = 0 THEN 0 ELSE SUM(num / div) END)
       ELSE -1
  END AS result
FROM data
GROUP BY cond

有什么解决方案可以避免 divisor is equal to zero 错误？

编辑

这个查询工作正常：

WITH data AS (SELECT 1 AS cond, 10 AS num, 0 AS div FROM DUAL)
SELECT
  CASE WHEN cond = 2 THEN (CASE WHEN MAX(div) = 0 THEN 0 ELSE 1 END)
       ELSE -1
  END AS result
FROM data
GROUP BY cond

Answer 1

使用

CASE WHEN cond = 2 
     THEN SUM(case when div = 0 then 0 else num / div end)
     ELSE -1
END

Oracle CASE 短路不能按组工作

Oracle CASE short-circuit not working in group by

oracle

case

short-circuiting