An Introduction to Database Systems

An Introduction to Database System

SQL (1

3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 Select

3.4.2 [.] [.]=>== 90 /* */

[38] SELECT Student.SnoSnameCnameGrade FROM StudentSCCourse /**/ WHERE Student.Sno = SC.Sno and SC.Cno = Course.Cno

3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 Select

()SELECT-FROM-WHEREWHEREHAVING

()

SELECT Sname /*/*/ FROM Student WHERE Sno IN SELECT Sno /*/*/ FROM SC WHERE Cno= ' 2 '

() ORDER BY SQL

WHERE

3.4.3 IN ANYSOMEALL EXISTS

IN[39] SELECT Sdept FROM Student WHERE Sname= ' ' CS

IN CS SELECT SnoSnameSdept FROM Student WHERE Sdept= ' CS '

IN SELECT SnoSnameSdept FROM Student WHERE Sdept IN (SELECT Sdept FROM Student WHERE Sname= )

IN [39] SELECT S1.SnoS1.SnameS1.Sdept FROM Student S1Student S2 WHERE S1.Sdept = S2.Sdept AND S2.Sname = ''

IN[40] SELECT SnoSname Student FROM Student SnoSname WHERE Sno IN (SELECT Sno SC FROM SC 3 WHERE Cno IN (SELECT Cno Course FROM Course 3 WHERE Cname= ) );

IN[40] SELECT SnoSname FROM StudentSCCourse WHERE Student.Sno = SC.Sno AND SC.Cno = Course.Cno AND Course.Cname=

3.4.3 IN ANYSOMEALL EXISTS

>=ANYALL

[39] = IN SELECT SnoSnameSdept FROM Student WHERE Sdept = (SELECT Sdept FROM Student WHERE Sname= )

SELECT SnoSnameSdept FROM Student WHERE ( SELECT Sdept FROM Student WHERE Sname= ) = Sdept

41 SELECT Sno Cno FROM SC x WHERE Grade >=(SELECT AVG(Grade) FROM SC y WHERE y.Sno=x.Sno);

1. SCxxSno200215121 SELECT AVG(Grade) FROM SC y WHERE y.Sno='200215121';2. 88 SELECT Sno Cno FROM SC x WHERE Grade >=88

3. 2002151211 2002151213 4.13SC: 2002151211 2002151213 2002151222

3.4.3 IN ANYSOMEALL EXISTS

ANYSOMEALL ANYALL

ANYSOMEALL > ANY > ALL< ANY < ALL>= ANY >= ALL