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Abdullah
Asked: 2024-08-22 15:22:15 +0800 CST

我如何才能像主查询一样按子查询进行分组？

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我如何才能像主查询一样应用分组子查询？

这是查询：

select a.clinic_no , 
b.CLINIC_DESC_A , 
a.doctor_no , 
c.STAFF_NATIVE_NAME , 
count(DISCHARGE_FROM_CLINIC) , 
(select count(patient_no) from trng.opd_visits_history WHERE event_date BETWEEN 20240815 and 20240822) as "Total"
from trng.opd_visits_history a , trng.hospital_clinics b  , trng.hospital_staff c 
WHERE event_date BETWEEN 20240815 and 20240822
 and a.CLINIC_NO = b.CLINIC_NO
and a.DOCTOR_NO = c.STAFF_NO 
and b.DOCTOR_NO = c.STAFF_NO
and a.HOSPITAL_NO = 720022
and b.HOSPITAL_NO = 720022
and c.HOSPITAL_NO = 720022  
AND a.DISCHARGE_FROM_CLINIC = 1
group by a.clinic_no , a.doctor_no , b.CLINIC_DESC_A , c.STAFF_NATIVE_NAME

输出如下：

clinic no       doctor no            discharge from clinic    total 
   10               22                         5                1230
   12               15                         4                1230 
   16               19                         7                1230
   20               13                         2                1230

我需要像这样按子查询进行分组：

select count(patient_no) from trng.opd_visits_history WHERE event_date BETWEEN 20240815 and 20240822 group by clinic_no , doctor_no

当我在子查询中使用 group by 时显示错误

ORA-01427 single row subquery returns more than one row
oracle

1 个回答

  1. Best Answer

    您正在尝试使用相关子查询，但是 - 您没有在其表和外部表之间应用任何关联。它必须只返回一行（值），但是 - 当您将group by子句放入其中时 - 它会导致返回多行，并且您会收到错误。

    类似这样的事情可能会发生（我也JOIN编辑了表格上的公共列并让WHERE子句过滤结果行）：

      SELECT a.clinic_no,
         b.clinic_desc_a,
         a.doctor_no,
         c.staff_native_name,
         COUNT (discharge_from_clinic),
         (SELECT COUNT (patient_no)
            FROM trng.opd_visits_history h
           WHERE     h.clinic_no = a.clinic_no                            --> this
                 AND h.doctor_no = a.doctor_no                            --> this
                 AND event_date BETWEEN 20240815 AND 20240822) AS "Total"
    FROM trng.opd_visits_history a
         JOIN trng.hospital_clinics b
            ON     a.clinic_no = b.clinic_no
               AND a.hospital_no = b.hospital_no
         JOIN trng.hospital_staff c
            ON     a.doctor_no = c.staff_no
               AND b.doctor_no = c.staff_no
               AND c.hospital_no = a.hospital_no
   WHERE     event_date BETWEEN 20240815 AND 20240822
         AND a.hospital_no = 720022
         AND a.discharge_from_clinic = 1
GROUP BY a.clinic_no,
         a.doctor_no,
         b.clinic_desc_a,
         c.staff_native_name
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