mysql - 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IF在一个案例中放置一个但得到一个错误（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，而不是在单个语句中组装条件。

真的，你只需要CASE使用它的其他语法格式在里面嵌套另一个CASE WHEN <condition> THEN <value>：

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

您可以将其重写为：

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