sql - 如何查找不同表中的行数

Question

我想从两个不同的表中获取数据，一个表包含学生总数，另一个表包含特定学生信息我如何获得学生人数 我想显示 name , code, totalstudent 和 no.of ngo student

select 
       a.name as name, a.school_code as CODE, 
       a.num_of_student as totalstudent,
       b.COUNT (ngo_student_name) as total_student 
from 
      ngo_student as a 
      INNER JOIN student_details as b on a.name=b.ngo_student_name 
GROUP BY
      b.ngo_student_name

此查询显示错误，请指导我 谢谢

Answer 1

尝试以下 - 您的 count(b.ngo_student_name) 而不是 b.count(ngo_student_name) 以及选择列表中的其他列应该在 group by 子句中

select 
       a.name as name, a.school_code as CODE, 
       count(a.num_of_student) as totalstudent,
       COUNT(b.ngo_student_name) as total_student 
from 
      ngo_student as a 
      INNER JOIN student_details as b on a.name=b.ngo_student_name 
GROUP BY
      a.name,a.school_code