在SQL中，如何显示正在学习多个科目的学生？

Question

例如 - 表名= TABLE

StudentID | SubCode | SubName
-----------------------------
    1          M1       Math
    1          S1       Science
    1          E1       English
    2          H1       History
    3          G2       Geography
    4          M1       Math    

我们可以这样显示答案吗？

studentid | SubCode | SubName
---------------------------------
    1          M1       Math
    1          S1       Science
    1          E1       English

Answer 1

带有IN()子句的HAVING子查询应该这样做：

SELECT * 
FROM table
WHERE StudentID IN (
  SELECT 
    StudentID
  FROM table
  GROUP BY userid
  HAVING COUNT(*) > 1
)

Answer 2

SELECT DISTINCT T1.*
  FROM YourTable AS T1
       INNER JOIN YourTable AS T2
          ON T1.StudentID = T2.StudentID
             AND T1.SubCode <> T2.SubCode;