mysql中触发器的创建

假设有两张表`class`，`student`；这两张表中存的都是学生的id和班机的id；如果向student表中插入数据同时数据也更新到class表中；下面分别是表的创建语句和触发器；

CREATE TABLE `class` (
  `classID` int(11) DEFAULT NULL,
  `stuID` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `student` (
  `stuID` int(11) DEFAULT NULL,
  `classID` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TRIGGER `tri_stuInsert` AFTER INSERT ON `student` FOR EACH ROW

begin
  declare s int;
  declare c int;
  set s = (select stuID from student where stuID =new.stuID );
  set c = (select classID from student where stuID =new.stuID );
  insert into class (stuID,classID) values(s,c);
end;

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下面是在navicat for mysql中创建触发起的截图：