Question

RDMBS：Oracle 嵌套查询是一项要求。

我试图收集2014年3月预约的所有患者，并展示他们看到的医生，以及他们被诊断出患有什么。然后显示约会ID，患者姓名，年龄，性别和电话，并显示医生姓名和电话。我能够完成大部分工作，直到我问到患者被诊断出患有什么。

此代码允许我访问2014年3月的患者和医生记录：

Select Appointment.appointmentid, patient.surname ||','|| patient.given as     Patient, trunc(((sysdate-patient.dob)/365),0) as Patient_Age, patient.phonehome as Patient_Contact, doctor.Surname ||','|| doctor.given as Doctor, doctor.phone as Doctor_Contact
from doctor, patient, appointment 
where doctor.doctorid=appointment.doctorid
and patient.patientid=appointment.patientid
and extract(month from dateofappointment) = '03'
and extract(year from dateofappointment) = '2014';

但是一旦我在嵌套查询中进行诊断，我就会收到错误。

代码：

Select Appointment.appointmentid, patient.surname ||','|| patient.given as Patient, trunc(((sysdate-patient.dob)/365),0) as Patient_Age, patient.phonehome as Patient_Contact, disease.name as Diagnosis, doctor.Surname ||','|| doctor.given as Doctor, doctor.phone as Doctor_Contact
from doctor, patient, appointment 
where disease.name in (select disease.name
from disease
where disease.diseaseid=diagnosed.diseaseid
and diagnosed.appointmentid=appointment.appointmentid)
and doctor.doctorid=appointment.doctorid
and patient.patientid=appointment.patientid
and extract(month from dateofappointment) = '03'
and extract(year from dateofappointment) = '2014';

任何更正或建议将不胜感激。

Answer 1

您没有引用disease表。您可以像这样重写查询：

Select 
  Appointment.appointmentid, 
  patient.surname ||','|| patient.given as Patient, 
  trunc(((sysdate-patient.dob)/365),0) as Patient_Age, 
  patient.phonehome as Patient_Contact, 
  disease.name as Diagnosis, 
  doctor.Surname ||','|| doctor.given as Doctor, 
  doctor.phone as Doctor_Contact
from doctor
inner join appointment on doctor.doctorid         = appointment.doctorid
inner join patient     on patient.patientid       = appointment.patientid
inner join diagonsed   on diagnosed.appointmentid = appointment.appointmentid
inner join disease     on disease.diseaseid       = diagnosed.diseaseid
where extract(month from dateofappointment) = '03'
  and extract(year from dateofappointment) = '2014';

或者，使用相同的嵌套查询，您可以像这样重写它：

Select 
  Appointment.appointmentid, 
  patient.surname ||','|| patient.given as Patient, 
  trunc(((sysdate-patient.dob)/365),0) as Patient_Age, 
  patient.phonehome as Patient_Contact, 
  disease.name as Diagnosis, 
  doctor.Surname ||','|| doctor.given as Doctor, 
  doctor.phone as Doctor_Contact
from doctor, appointment, patient, diagnosed, disease
where doctor.doctorid = appointment.doctorid
and appointment.patientid = patient.patientid
and diagnosed.appointmentid=appointment.appointmentid
and disease.diseaseid=diagnosed.diseaseid
and disease.name in (select disease.name
                       from disease
                       where disease.diseaseid=diagnosed.diseaseid)
and extract(month from dateofappointment) = '03'
and extract(year from dateofappointment) = '2014';

连接和嵌套查询 - 多个表（4+）

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