sql - 使用 case 在 where 子句中的两个句子之间进行选择 (Oracle)

Question

我正在创建一个函数，我需要根据参数值 (PTIPO) 在两个句子之间进行选择

下面是我的代码

SELECT SUM(
    CASE PTIPO
      WHEN 0 THEN (CASE WHEN (A.NT = 0) THEN A.VALOR ELSE 0 END)
      WHEN 1 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE 0 END)
      WHEN 2 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE -A.VALOR END) 
    END)
INTO nresp
FROM mov_caja a
JOIN enc_movp b ON a.docid = b.docid
JOIN c_caja c ON a.cajaid = c.cajaid
WHERE c.cajaid = pcajaid AND( 
    CASE WHEN(PTIPO = 2) --this is what causes the issue.
    THEN
    b.cod_compro = ncompini OR (b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin)
    ELSE
    b.cod_compro != ncompini AND b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin
    END);

错误是“缺少关键字”，但我知道问题出在最后一个 CASE 上。我还能如何在句子之间进行选择。这种情况是正确的方法还是我应该使用其他声明？

Answer 1

case 可以返回一个值，但不能返回一个表达式。这应该可以解决问题，尽管我觉得它甚至可以更简单:

SELECT SUM(
    CASE PTIPO
      WHEN 0 THEN (CASE WHEN (A.NT = 0) THEN A.VALOR ELSE 0 END)
      WHEN 1 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE 0 END)
      WHEN 2 THEN (CASE WHEN (A.NT = 1) THEN A.VALOR ELSE -A.VALOR END) 
    END)
INTO nresp
FROM mov_caja a
JOIN enc_movp b ON a.docid = b.docid
JOIN c_caja c ON a.cajaid = c.cajaid
WHERE 
  c.cajaid = pcajaid AND
  ( 
    (PTIPO = 2 and (b.cod_compro = ncompini OR b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin))
OR
    (PTIPO <> 2 and (b.cod_compro != ncompini AND b.fecha_mov BETWEEN pfecha_ini AND pfecha_fin))
  )