SQL:如何删除行; 使用Multiply Returns从另一个表中保护"WHERE"的时候

Question

询问

    DELETE FROM TEMPSchedules 
           WHERE StudentID = ( Select StudentID 
                               From Students 
                               Where Ref = 'H1007')

错误信息

子查询返回的值超过1.当子查询跟随=,!=,<,<=,>,> =或子查询用作表达式时,不允许这样做.

问题

现在的问题是每个"参考小组"都有超过1名学生.那我应该怎么处理呢.谢谢

Answer 1

  DELETE FROM TEMPSchedules 
           WHERE StudentID  in ( Select distinct StudentID 
                               From Students 
                               Where Ref = 'H1007')