Using aggregation on nested tables - sql, PL-SQL Programming

Assignment Help:

Using Aggregation on Nested Tables

Example is the most direct translation of its counterpart in the theory book that can be obtained in SQL but it is so over-elaborate that no SQL practitioner would consider using it. It uses the aggregate operator COUNT on the table values for column ExamResult to obtain the number of students who sat each exam. Unfortunately, as already noted, we cannot operate directly on ExamResult as a FROM clause element. Instead, we need to use an artifice that is specially devised for the sake of this example.

Example: How many students sat each exam

WITH C_ER AS (

 SELECT CourseId,

 CAST (

 TABLE (SELECT DISTINCT StudentId, Mark

 FROM EXAM_MARK AS EM

 WHERE EM.CourseId = C.CourseId)

 AS ROW ( StudentId SID, Mark INTEGER ) MULTISET)

 AS ExamResult

 FROM COURSE AS C)

SELECT CourseId, (SELECT COUNT (*)

FROM TABLE (ER (ExamResult)) AS t) AS n

FROM C_ER


Related Discussions:- Using aggregation on nested tables - sql

Program, heap sort program in pl/sql

heap sort program in pl/sql

Prepare a slq project, Project Description: I want to write some SQL st...

Project Description: I want to write some SQL statements. The things I need are between pages 5-7. The only problem is that i want it till tomorrow. Skills required is SQL

Case sensitivity-naming conventions, Case Sensitivity Similar to all the...

Case Sensitivity Similar to all the identifiers, the variables, the names of constants, and parameters are not case sensitive. For illustration, PL/SQL considers the following n

Using savepoints, Using Savepoints The scope of the savepoint is a tra...

Using Savepoints The scope of the savepoint is a transaction in which it is defined. The Savepoints defined in the major transaction are not related to the savepoints defined

Heap sort algorithm in pl sql, I want to implement heap sort algorithm in p...

I want to implement heap sort algorithm in pl sql please share the source code for guidance

%rowcount - implicit cursor attributes, %ROWCOUNT The %ROWCOUNT yields...

%ROWCOUNT The %ROWCOUNT yields the number of rows affected by the INSERT, UPDATE, or DELETE statement, or returned by a SELECT INTO statement. The %ROWCOUNT yields zero when a

Features of pl/sql, Main features of PL/SQL A good way to get familiar ...

Main features of PL/SQL A good way to get familiar with PL/SQL is to look at a sample program. The below program processes an order for tennis rackets. At first, it declares a

Parameter aliasing, Parameter Aliasing   To optimize the subprogram ca...

Parameter Aliasing   To optimize the subprogram call, the PL/SQL compiler can decide between the two techniques of the parameter passing. With the by-value techniques, the v

Controlling cursor variables, Controlling Cursor Variables You use 3 s...

Controlling Cursor Variables You use 3 statements to control the cursor variable: OPEN-FOR, FETCH, & CLOSE. At First, you OPEN a cursor variable FOR a multi-row query. Then, y

Exit statement - syntax, EXIT Statement   You can use the EXIT stateme...

EXIT Statement   You can use the EXIT statement to exit a loop. The EXIT statement has 2 forms: the conditional EXIT WHEN and the unconditional EXIT. With the either form, you

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd