如何添加两个复杂的 SQL 查询并在单个查询中获取输出？

Question

我是编码新手，正在准备 SQL 命令，但卡在了一步。下面是主要的 SQL 查询：

select 
distinct 
hap.position_code as RequisitionNumber, 
COALESCE(hap.attribute10,'UNIVERSAL') as RequisitionType, hap.name as 
RequisitionTitle, 
paam1.job_id as RequisitionTemplate, COALESCE(hap.attribute11,'1') as 
NumberToHire, 

pu.username as HiringManagerLogin, 

paam1.job_id as JobField, 
hap.full_part_time as Schedules, hap.position_code as PositionCode  
from hr_all_positions hap, per_all_assignments_m paam1, per_users pu 
where hap.position_id = paam1.position_id
and hap.position_id in
(
select distinct paam.position_id from per_all_assignments_m paam, 
per_periods_of_service ppos 
where paam.person_id = ppos.person_id and paam.position_id is not null and 
ppos.actual_termination_date >= sysdate
)

在上面的查询中，我从下面附加的另一个查询中获取 pu.username 的值：

select pu.username from per_users pu where person_id = (
select pmhd.manager_id from PER_MANAGER_HRCHY_DN pmhd, 
per_periods_of_service ppos 
where pmhd.person_id = ppos.person_id and pmhd.IMMEDIATE_REPORTEE_ASG_ID is 
not null 
and pmhd.EFFECTIVE_END_DATE = ppos.actual_termination_date and 
ppos.actual_termination_date >= sysdate 
and pmhd.person_id = (select distinct paam.person_id from 
per_all_assignments_m paam, per_periods_of_service ppos 
where paam.person_id = ppos.person_id and paam.position_id is not null and 
ppos.actual_termination_date >= sysdate) 
)

现在，当我像下面这样加入两个查询时：

select 
distinct 
hap.position_code as RequisitionNumber, 
COALESCE(hap.attribute10,'UNIVERSAL') as 
RequisitionType, hap.name as RequisitionTitle, 
paam1.job_id as RequisitionTemplate, COALESCE(hap.attribute11,'1') as 
NumberToHire, 

pu.username as HiringManagerLogin, 

paam1.job_id as JobField, 
hap.full_part_time as Schedules, hap.position_code as PositionCode  
from hr_all_positions hap, per_all_assignments_m paam1, per_users pu 
where hap.position_id = paam1.position_id and paam1.person_id = pu.person_id
and pu.person_id = (
select pmhd.manager_id from PER_MANAGER_HRCHY_DN pmhd, per_periods_of_service 
ppos 
where pmhd.person_id = ppos.person_id and pmhd.IMMEDIATE_REPORTEE_ASG_ID is 
not null 
and pmhd.EFFECTIVE_END_DATE = ppos.actual_termination_date and 
ppos.actual_termination_date >= sysdate 
and pmhd.person_id = (select distinct paam.person_id from 
per_all_assignments_m 
paam, per_periods_of_service ppos 
where paam.person_id = ppos.person_id and paam.position_id is not null and 
ppos.actual_termination_date >= sysdate) 
)
and hap.position_id in
(
select distinct paam.position_id from per_all_assignments_m paam, 
per_periods_of_service ppos 
where paam.person_id = ppos.person_id and paam.position_id is not null and 
ppos.actual_termination_date >= sysdate
)

我正在尝试这是 Oracle 数据库没有数据输出，我不明白为什么？

请帮助我！！

提前致谢，希瓦姆

Answer 1

老实说，您的最终查询输出看起来像是其他两者的适当组合。但是，由于附加的连接条件，您可能得不到任何输出：

paam1.person_id = pu.person_id

这不在您的任何一个原始查询中，并且每一行都可能无法满足此连接条件。尝试删除它以查看是否输出任何行。尝试将其添加到您的第一个查询中。如果输出行，那么这可能意味着您在 pu.person_id 上的附加过滤器非常有选择性。

如何添加两个复杂的 SQL 查询并在单个查询中获取输出？

How to add two complex SQL Queries and get output in single query?

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