Oracle SQL-如果在Where子句中寫入案例

Question

我正在編寫一個查詢來爲員工提取轉帳。這意味着在行之前的那行就是行爲'轉移'。一些員工在同一日期有轉移行爲和其他行爲。但是，我的查詢獲取了Transfer日期爲<的日期。我想寫一些這樣的事情： -

select * 
from per_all_assignments_m paam 
where paam.effective_start_date= 
     (case if (paam.effective_start_date= 
       (select max(paam1.effective_start_date) 
       from per_all_assignments_m paam1 
       where paam1.person_id=paam.person_id and 
         paam.assignment_id=paam1.assignment_id and 
         paam1.action_code <> 'TRANSFER' and 
         paa1.effective_latest_change='N') 
       ) 
      then paam.effective_start_date  
      else (paam.effective_start_date= 
        (select max(paam1.effective_stat_date) 
        from per_all_assignments_m paam1 
        where paam.person_id=paam1.person_id and 
         paam.assignment_id=paam1.assignment_id and 
         paam1.effective_start_date < 
         (select max(paam2.effective_start_date) 
          from per_all_assignments_m paam2 
          where paam2.action_code='TRANSFER' and 
           paam1.person_id = paam2.person_id and 
           paam1.assignment_id=paam2.assignment_id) 
       ) 
       ) 
    ) 

Oracle中可能嗎？

Answer 1

是的，這是可能的

SELECT 
    * 
FROM 
    per_all_assignments_m paam 
WHERE 
    paam.effective_start_date = 
    (
     CASE 
     WHEN 
      paam.effective_start_date = 
      (
       SELECT 
       MAX(paam1.effective_start_date) 
       FROM 
       per_all_assignments_m paam1 
       WHERE 
       paam1.person_id = paam.person_id AND 
       paam.assignment_id = paam1.assignment_id AND 
       paam1.action_code <> 'TRANSFER' AND 
       paa1.effective_latest_change = 'N' 
      ) 
     THEN paam.effective_start_date 
     ELSE 
      (
      SELECT 
       MAX(paam1.effective_stat_date) 
      FROM 
       per_all_assignments_m paam1 
      WHERE 
       paam.person_id = paam1.person_id AND 
       paam.assignment_id = paam1.assignment_id AND 
       paam1.effective_start_date < 
       (
       SELECT 
        MAX(paam2.effective_start_date) 
       FROM 
        per_all_assignments_m paam2 
       WHERE 
        paam2.action_code = 'TRANSFER' AND 
        paam1.person_id = paam2.person_id AND 
        paam1.assignment_id = paam2.assignment_id 
      ) 
     ) 
     END -- closing END for case when.. 
    ) 

Answer 2

應該有在前面的選擇請求