假设有 3 个这样的表：
Teacher:
teacher_id, name, ...
Student:
student_id, teacher_id, ...
Class:
class_id, teacher_id, ...
是否有 SQL 查询来获取为每位教师分配了多少学生和班级？
结果应该是这样的：
teacher_id name students classes
t_001 AAA 3 2
t_002 BBB 1 2
...
尝试这样的事情：
SELECT
t.teacher_id, t.name,
Classes = (SELECT COUNT(*) FROM Class c WHERE c.teacher_id = t.teacher_id),
Students = (SELECT COUNT(*) FROM Student s WHERE s.teacher_id = t.teacher_id)
FROM teacher t
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
