如何在SQL中按值按名称进行grup？

我需要使用SQL和make from：

Student | Subject 
alpha |Geo
alpha| Maths   
beta |Maths
beta | Geo
gamma |PE
delta  |Maths
alpha | Pe

输出：贝塔

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哪个学生有地理数学，但没有体育？

你可以使用聚合和

having

：

select student
from t
group by student
having sum(case when subject = 'Geo' then 1 else 0 end) > 0 and
       sum(case when subject = 'Maths' then 1 else 0 end) > 0 and
       sum(case when subject = 'PE' then 1 else 0 end) = 0;

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一种方法是使用LISTAGG形成每个学生所选科目的列表，然后确定您所关心的科目是否在列表中。比如：

SELECT STUDENT
  FROM (SELECT STUDENT,
               LISTAGG(SUBJECT, ',') WITHIN GROUP (ORDER BY STUDENT) AS SUBJECTS
          FROM STUDENTS
          GROUP BY STUDENT)
  WHERE INSTR(SUBJECTS, 'Geo') <> 0 AND
        INSTR(SUBJECTS, 'Maths') <> 0 AND
        INSTR(SUBJECTS, 'Pe') = 0

WITH cteGeo_students
       AS (SELECT STUDENT
             FROM STUDENTS
             WHERE SUBJECT = 'Geo'),
     cteMaths_students
       AS (SELECT STUDENT
             FROM STUDENTS
             WHERE SUBJECT = 'Maths'),
     ctePe_students
       AS (SELECT STUDENT
             FROM STUDENTS
             WHERE SUBJECT = 'Pe')
SELECT g.STUDENT
  FROM cteGeo_students g
  INNER JOIN cteMaths_students m
    ON m.STUDENT = g.STUDENT
  LEFT OUTER JOIN ctePe_students p
    ON p.STUDENT = g.STUDENT
  WHERE p.STUDENT IS NULL