CURSOR c1 IS SELECT course_number, instructor FROM courses_tbl FOR UPDATE OF instructor; If you plan on updating or deleting records that have been referenced by a SELECT FOR UPDATE statement, you can use theWHERE CURRENT OFstatement.
(1).写一个SQL语句,查询选修了’计算机原理’的学生学号和姓名 select 学号,姓名 from Student where 学号 in (select 学号 from Sc where 课程编号 in (select 编号 from Course where 课程名称=’计算机原理’ ) ); (2).写一个SQL语句,查询’周星驰’同学选修了的课程名字 select 课程名称 from Course whe...
string strSql = "UPDATE TA_TeacherCourseStudentLink WITH(UPDLOCK) SET IsEvluation='Y' WHERE TeacherID=@TeacherID AND StudentID=@StudentID AND CourseID=@CourseID"; //参数 SqlParameter[] paras = new SqlParameter[]{ new SqlParameter("@TeacherID",enTeacherCourseStudent.TeacherID), //教师ID ne...
select * from tb1_1172691 tb1 CROSS join tb2_1172691 tb2 where tb1.sid<5 order by 1,2,3,4,5 limit 1 FOR UPDATE SKIP LOCKED; --事务1 end; 3.select xx from a,b where a.id=b.id; --事务1 begin; select * from tb1_1172691 tb1,tb2_1172691 tb2 where tb1.sid=tb2.student_id...
select*fromemp_vw2; 复杂视图不能进行 DML 操作 updateemp_vw2 setavg_sal =10000 wheredepartment_id =100; 2. 序列:用于生成一组有规律的数值。(通常用于为主键设置值)createsequenceemp_seq1 startwith1 incrementby1 maxvalue10000 minvalue1
SELECT course_name, semester_number, count('hello') FROM choose_course GROUP BY course_name, semester_number; 多个字段分组查询时,先按照第一个字段分组,如果第一个字段有相同值,则把分组结果再按第二个字段进行分组,以此类推 如果第一个字段每个值都是唯一的,则不会按照第二个字段再进行分组了 group by...
"TeacherName,CourseID,CourseName,CourseTypeID,CourseTypeName," + "StudentID,StudentName,IsEvluation FROM TA_TeacherCourseStudentLink WITH(NOLOCK) " + "WHERE StudentID = @StudentID"; //参数 SqlParameter[] para = new SqlParameter[] {
Description:SELECT FOR Update does no lock the selected rows: 1) Client A: Select * from table X where ID=1 for update Dont Commit! 2) Client B: Select * from table X where ID=1 for update The querey returns without waiting for the Client A to commit. I have tried the same on ...
解析 USE Xk GO CREATE TRIGGER SetWillNum ON StuCou FOR INSERT, UPDATE AS UPDATE Course SET Num=Num+1 WHERE CouNo=(SELECT CouNo FROM INSERTED) UPDATE Course SET Num=Num-1 WHERE CouNo=(SELECT CouNo FROM DELETED) 试题D参考答案 设计题...
See Section 6.4.3. To ensure that the update log/binary log can be used to re-create the original tables, MySQL will not allow concurrent inserts during INSERT ... SELECT. You can, of course, also use REPLACE instead of INSERT to overwrite old rows....