sql - 如何根据 SQL 中的不同问题显示所有数据？

Question

即使满足第一个条件，我如何循环遍历所有条件？例如：

CASE WHEN first_condition is NOT NULL
          THEN ppp."WEIGHT"
     WHEN second_condition IS NOT NULL
          THEN ppp."WEIGHT"

结果将是：

first_condition  | weight 
second_condition | weight

标签： sql

Answer 1

对于每个条件，您必须有不同的列：

CASE 
  WHEN first_condition is NOT NULL THEN ppp."WEIGHT"
  ELSE NULL 
  END AS Condition1
CASE 
  WHEN second_condition IS NOT NULL THEN ppp."WEIGHT"
  ELSE NULL 
  END AS Condition2