如果条件在情况下

Question

我正在将一些 MySQL 5.0 函数转换为 Oracle 11g。

我需要在一个案例中放置一个IF，但出现错误（缺少右括号） 这是我的代码

SELECT SUM(
    CASE PTIPO
      WHEN 0 THEN (SELECT IF(A.NT = 0) THEN A.VALOR ELSE 0 END IF FROM DUAL)
      WHEN 1 THEN (SELECT IF(A.NT = 1) THEN A.VALOR ELSE 0 END IF FROM DUAL)
      WHEN 2 THEN (SELECT IF(A.NT = 1) THEN A.VALOR ELSE -A.VALOR END IF FROM DUAL)
    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

Answer 1

IF / ELSE 用于函数内部的流控制和准备好的语句，而不是用于在单个语句中组装条件。

真的，您只需要使用其他语法格式CASE WHEN <condition> THEN <value> 在内部嵌套另一个CASE：

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

Answer 2

你可以改写为：

SELECT SUM(
    CASE 
      WHEN PTIPO = 0 and A.NT  = 0 THEN A.VALOR 
      WHEN PTIPO = 0 and A.NT <> 0 THEN 0
      WHEN PTIPO = 1 and A.NT  = 1 THEN A.VALOR 
      WHEN PTIPO = 1 and A.NT <> 1 THEN 0
      WHEN PTIPO = 2 and A.NT  = 1 THEN A.VALOR 
      WHEN PTIPO = 2 and A.NT <> 1 THEN -A.VALOR 
    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