mysql - SQL查询未运行

Question

当我在 phpmyadmin 上运行以下查询时，它会给出以下错误

INSERT INTO `infrastructure_support_info`(`s_no`, `student_no`, `books_availability`, `basic_requirements`, `technological_support`, `study_material`, `resource_availability`, `cleaniliness_of_class`)
VALUES ('', '', '$availabilityOfBooks', '$basicRequirements', '$technologicalSupport', '$photocopyOfStudyMaterial', '$availabilityOfOtherResources', '$cleanlinessOfClass')

#1452 - Cannot add or update a child row: a foreign key constraint fails (feedback_system_db.infrastructure_support_info, CONSTRAINT user_std_no FOREIGN KEY (student_no) REFERENCES user_master (student_no))

Answer 1

您的表引用了另一个表。如果您想将该链接留空，请使用 null 而不是空白字符串 ''。