SQL : How to Delete Rows; when defending “WHERE” from another table with Multiply Returns

Question

查询

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

错误信息

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

问题

现在的问题是每个“Ref Group”都有超过 1 个 Student。那么我该如何处理呢。谢谢

Answer 1

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