sql嵌套case语句

Question

有谁知道这个嵌套的 select 语句有什么问题？它提示缺少 )，但我不明白为什么它不起作用(我已经忽略了语句的其他部分)

Select
(CASE WHEN REQUESTS.grade_id = 1 THEN
      (CASE WHEN  ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
           ELSE 'No'
      END)
 ELSE CASE WHEN REQUESTS.grade_id = 2 THEN
      (CASE ((date_completed-date_submitted)*24*60) <=120 THEN 'Yes'
           ELSE 'No'
      END) 
 ELSE CASE WHEN REQUESTS.grade_id = 3 THEN
     (CASE ((date_completed-date_submitted)*24*60)<=14400 THEN 'Yes'
          ELSE 'No'
     END)
 END)in_SLA

如果我只是这样做

    Select
       (CASE WHEN REQUESTS.grade_id = 1 THEN
           (CASE WHEN  ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
               ELSE 'No'
            END)
       END) in_sla

它工作正常!

非常感谢任何帮助

米

抱歉，我迟到了，我错过了嵌套案例的时间

Answer 1

应该是:

Select
(CASE WHEN REQUESTS.grade_id = 1 THEN
      (CASE WHEN  ((date_completed-date_submitted)*24*60)<=30 THEN 'Yes'
           ELSE 'No'
      END)
      WHEN REQUESTS.grade_id = 2 THEN
      (CASE ((date_completed-date_submitted)*24*60) <=120 THEN 'Yes'
           ELSE 'No'
      END) 
      WHEN REQUESTS.grade_id = 3 THEN
     (CASE ((date_completed-date_submitted)*24*60)<=14400 THEN 'Yes'
          ELSE 'No'
     END)
 END)in_SLA

即对于每种情况，只是“WHEN”而不是“ELSE CASE WHEN”。

我很想简化为:

Select
CASE WHEN (REQUESTS.grade_id = 1 AND (date_completed-date_submitted)*24*60 <= 30)
       OR (REQUESTS.grade_id = 2 AND (date_completed-date_submitted)*24*60 <=120)
       OR (REQUESTS.grade_id = 3 AND (date_completed-date_submitted)*24*60 <=14400)
     THEN 'Yes'
     ELSE 'No'
 END in_SLA