#语句格式#CREATE VIEW <视图名>[(<列名>,[,<列名>])]AS<子查询> [WITH CHECK OPTION]#CREATE VIEW IS_Student#AS SELECT Sno,Sname,Sage #FROM student#WHERE sdept='is';#视图没有主码#基于多个表创建视图CREATE VIEW IS_S1(Sno,Sname,Grade)AsSELECT student.Sno,Sname,GradeFROM student,scWHERE sdept='IS'ANDstudent.Sno=sc.Sno o='1';CREATE VIEW IS_S2AS SELECT Sno,Sname,Grade FROM IS_S1WHERE Grade>=90;#定义一个反应学生年份的视图CREATE VIEW BT_S(Sno,Sname,Sbirth)ASSELECT Sno,Sname,-SageFROM student;#将学生的学号以及平均成绩定义为一个视图CREATE VIEW S_G(Sno,Gavg)ASSELECT Sno,AVG(Grade)FROM scGROUP BY Sno;#将学生表所有的女生定义为一个视图CREATE VIEW F_Stuent(F_Sno,F_name,sex,age,dept)ASSELECT * FROM studentWHERE Ssex='女';#基本表与视图，mysql删除基本表，有关联视图不会提示
