我正在开发Oracle中的评估项目，并想知道如何确保CASE语句的结果不会显示在我的查询中。我尝试过使用ALIAS名称，但它不喜欢它，因为它是一个“无效的标识符”。有人告诉我你不能在'Where'子句中使用ALIAS名称？不确定这是否正确。
我确信这很简单，但我找不到问题。这是我到目前为止所做的工作：
--QUERY 1--
SELECT Department
, Full_Name_Supervisor
, Supervisor_Email
, Full_Name, Email_Address
, Start_Date
, Classification
, Job_Title
, State_or_Local_Fund
-- ,(extract(DAY from Start_Date)||'/'||extract(MONTH from Start_Date)||'/'||extract(YEAR from sysdate))
--START OF CASE STATEMENTS--
,(CASE WHEN Classification = 'CS' THEN
(CASE WHEN add_months(Start_Date, 3) BETWEEN trunc(Sysdate - 30) AND trunc(Sysdate - 1) THEN '3M 30 Days Past'
WHEN add_months(Start_Date, 3) BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN '3M Next 90 Days'
WHEN add_months(Start_Date, 6) BETWEEN trunc(Sysdate - 30) AND trunc(Sysdate - 1) THEN '6M 30 Days Past'
WHEN add_months(Start_Date, 6) BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN '6M Next 90 Days'
WHEN add_months(Start_Date, 12) BETWEEN trunc(Sysdate - 30) AND trunc(Sysdate - 1) THEN '12M 30 Days Past'
WHEN add_months(Start_Date, 12) BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN '12M Next 90 Days'
WHEN to_date(decode(extract(DAY from Start_Date)||'/'||extract(MONTH from Start_Date),'29/2','28/2',extract(DAY from Start_Date)||'/'||extract(MONTH from Start_Date))||'/'||extract(YEAR from sysdate),'dd/mm/yyyy') BETWEEN trunc(Sysdate - 30) AND trunc(Sysdate - 1) THEN 'Annual 30 Days Past'
WHEN to_date(decode(extract(DAY from Start_Date)||'/'||extract(MONTH from Start_Date),'29/2','28/2',extract(DAY from Start_Date)||'/'||extract(MONTH from Start_Date))||'/'||extract(YEAR from sysdate),'dd/mm/yyyy') BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN 'Annual Next 90 Days'
END)
WHEN Classification = 'AP' THEN
(CASE WHEN to_date('01-JAN'||(EXTRACT(YEAR FROM sysdate)+ 1),'DD-MON-YYYY') BETWEEN trunc(sysdate - 30) AND trunc(sysdate - 1) THEN 'Annual 30 Days Past'
WHEN to_date('01-JAN'||(EXTRACT(YEAR FROM sysdate)+ 1),'DD-MON-YYYY') BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN 'Annual Next 90 Days'
END)
WHEN Classification = 'ST' THEN
(CASE WHEN to_date('01-MAY'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(sysdate - 30) AND trunc(sysdate - 1) THEN 'Semester 30 Days Past'
WHEN to_date('01-MAY'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN 'Semester Next 90 Days'
WHEN to_date('01-AUG'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(sysdate - 30) AND trunc(sysdate - 1) THEN 'Semester 30 Days Past'
WHEN to_date('01-AUG'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN 'Semester Next 90 Days'
WHEN to_date('01-DEC'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(sysdate - 30) AND trunc(sysdate - 1) THEN 'Semester 30 Days Past'
WHEN to_date('01-DEC'||(EXTRACT(YEAR FROM sysdate)), 'DD-MON-YYYY') BETWEEN trunc(Sysdate) AND trunc(Sysdate + 89) THEN 'Semester Next 90 Days'
END)
END) AS Evaluation_Due --This is the last column which only Non-Null values should be shown.
FROM
--Query 2--
(SELECT DISTINCT
(SELECT Min(q2.effective_start_date)
FROM hr.per_all_assignments_f q2
WHERE q2.assignment_id = paaf.assignment_id
AND 'Evaluation_Due' > ' '
AND q2.job_id = paaf.job_id) AS Start_Date
,papf.email_address Email_Address
,papf.full_name Full_Name
,haou.name Department
,pjd.segment6 Classification
,pjd.segment9 Job_Title
,ppapf.full_name Full_Name_Supervisor
,ppapf.email_address Supervisor_Email
,(CASE when substr(pcak.segment1, 2,3) = '810' then 'State'
when substr(pcak.segment1, 2,3) = '010' then 'State'
ELSE 'Local'
END) State_or_Local_Fund
FROM hr.per_all_people_f papf,
hr.per_all_assignments_f paaf,
hr.per_all_people_f ppapf,
hr.hr_all_organization_units haou,
hr.per_jobs pj,
hr.per_job_definitions pjd,
hr.pay_cost_allocations_f pcaf,
hr.pay_cost_allocation_keyflex pcak
--Joining fields--
WHERE paaf.person_id = papf.person_id
AND papf.person_id = paaf.person_id
AND paaf.organization_id = haou.organization_id
AND pcak.cost_allocation_keyflex_id = pcaf.cost_allocation_keyflex_id
AND pcaf.assignment_id = paaf.assignment_id
AND pj.job_definition_id = pjd.job_definition_id
AND paaf.job_id = pj.job_id
AND ppapf.person_id (+) = paaf.supervisor_id
-- Truncating sysdate--
AND trunc(sysdate) BETWEEN papf.effective_start_date and papf.effective_end_date
AND trunc(sysdate) BETWEEN paaf.effective_start_date and paaf.effective_end_date
AND trunc(sysdate) BETWEEN pcaf.effective_start_date and pcaf.effective_end_date
AND trunc(sysdate) BETWEEN ppapf.effective_start_date (+) and ppapf.effective_end_date (+)
--Constraints--
AND (pjd.segment3 != 'E'
AND pjd.segment9 != 'Retiree'
AND pjd.segment6 IN ('CS','AP','ST')
AND paaf.assignment_status_type_id = 1
))
如果需要更多信息，请与我们联系。谢谢！