在此查询中,DISTINCT关键字不起作用。显示主题表中的重复主题。。有人能告诉我哪里搞错了吗?
SELECT DISTINCT
tutor_category_subject.subject_id,
GROUP_CONCAT(subject.subjects SEPARATOR ', ') AS subjects
FROM tutor_category_subject
INNER JOIN subject ON tutor_category_subject.subject_id = subject.subject_id
WHERE tutor_category_subject.tutor_id = 3;
我认为您需要一个按语句分组:
SELECT tutor_category_subject.subject_id,
GROUP_CONCAT(subject.subjects SEPARATOR ', ') AS subjects
FROM tutor_category_subject INNER JOIN
subject
ON tutor_category_subject.subject_id = subject.subject_id
WHERE tutor_category_subject.tutor_id = 3
group by tutor_category_subject.subject_id