高频 SQL 50 题(基础版)_2356. 每位教师所教授的科目种类的数量
高频 SQL 50 题(基础版)_2356. 每位教师所教授的科目种类的数量
select teacher_id ,count(distinct(subject_id)) as cnt
from Teacher
group by teacher_id
select teacher_id ,count(distinct(subject_id)) as cnt
from Teacher
group by teacher_id