Programming Languages for MIS

277

sQL

9.10.2 Subquery as an Alternative to GROUP BY

A subquery can be used as an alternative to the GROUP BY clause. For example, the

query in Listing9.23 is to show each student’s name along with the number of courses

she/ he has taken using a subquery.

Listing9.23: Subquery for Groups

SELECT tblStudent.StudentName,

(SELECT COUNT(*)

FROM tblGrading

WHERE tblStudent.StudentID=tblGrading.StudentID)

AS NumberOfCourses

FROM tblStudent;

e use of subquery for groups could cause confusion if the design of the subquery

is incorrect. For the beginner, the GROUP BY clause would be better than this type

of subquery.

9.10.3 Subquery—Determining an U