不是表达错误的分组（Oracle）

Question

下面是我在oracle 12c中的sql查询。我正在使用sqlplus。它提示错误“ORA-00979：不是GROUP BY表达式”。我不知道什么时候错了。请帮忙。

PROMPT Type the speciality
ACCEPT speciality PROMPT "Speciality: "
SELECT assignment.doctor_id, doctors.name, MAX(assignment.end_assignment) AS end_contract,
(SELECT doctor_availability.end_availability
 FROM doctor_availability
 JOIN doctor_specialities ON doctor_specialities.doctor_id = doctors.id
 AND UPPER(doctor_specialities.specialities) like UPPER('%&speciality%'))
FROM assignment
JOIN doctors ON doctors.id = assignment.doctor_id
JOIN doctor_availability ON doctor_availability.doctor_id = assignment.doctor_id
WHERE doctor_availability.end_availability > 'end_contract'
GROUP BY assignment.doctor_id;

Answer 1

通常，如果使用Group by子句，则必须将所选的所有字段放在那里，而不使用aggregateat函数。在您的情况下，您选择assignment.doctor_id，doctors.name而不使用聚合函数，但在group by子句中只有assignment.doctor_id。 试试这个

SELECT assignment.doctor_id, doctors.name, MAX(assignment.end_assignment) AS end_contract,
(SELECT doctor_availability.end_availability
 FROM doctor_availability
 JOIN doctor_specialities ON doctor_specialities.doctor_id = doctors.id
 AND UPPER(doctor_specialities.specialities) like UPPER('%&speciality%'))
FROM assignment
JOIN doctors ON doctors.id = assignment.doctor_id
JOIN doctor_availability ON doctor_availability.doctor_id = assignment.doctor_id
WHERE doctor_availability.end_availability > 'end_contract'
GROUP BY assignment.doctor_id, doctors.name

Answer 2

您需要在组中包含所有选择值。

PROMPT Type the speciality
ACCEPT speciality PROMPT "Speciality: "
SELECT assignment.doctor_id, doctors.name, MAX(assignment.end_assignment) AS end_contract,
(SELECT doctor_availability.end_availability
FROM doctor_availability
JOIN doctor_specialities ON doctor_specialities.doctor_id = doctors.id
AND UPPER(doctor_specialities.specialities) like UPPER('%&speciality%'))
FROM assignment
JOIN doctors ON doctors.id = assignment.doctor_id
JOIN doctor_availability ON doctor_availability.doctor_id = assignment.doctor_id
WHERE doctor_availability.end_availability > 'end_contract'
GROUP BY assignment.doctor_id, doctors.name, doctor_availability.end_availability;