Using rename in combination with join - sql, PL-SQL Programming

Assignment Help:

Using RENAME in combination with JOIN - SQL

Example gives pairs of ids of students having the same name, by joining two renamings of IS_CALLED. Example gives an equivalent expression in SQL.

Example: Renaming and joining

Student Sid1 is called Name and so is student Sid2

SELECT *

FROM   (SELECT StudentId AS Sid1, Name FROM IS_CALLED)

     NATURAL JOIN

     (SELECT StudentId AS Sid2, Name FROM IS_CALLED)

As before, the result sagely tells us that student S1 (Anne) has the same name as herself and also shows two pairings of S1 with S5 (both named Boris). The pairing of a student id with itself can be avoided by adding WHERE Sid1 < > Sid2 to the WHERE clause. The duplicate pairings can further be avoided by using < instead of < > in this addition, but that trick assumes that an ordering is defined for type SID, which is not necessarily the case.


Related Discussions:- Using rename in combination with join - sql

Using inner join, Using INNER JOIN INNER JOIN is used to retrieve the ...

Using INNER JOIN INNER JOIN is used to retrieve the data from all tables listed based on a condition of equality listed after keyword ON. If the condition is not meet, rows ar

Other monadic - sql, Other monadic - SQL In 2VL there are just 4 (2 2 ...

Other monadic - SQL In 2VL there are just 4 (2 2 ) monadic operators, of which negation is really the only "useful" one. When a third truth value is introduced we have 27 (3 3

Implicit cursor attributes, Implicit Cursor Attributes The Implicit cur...

Implicit Cursor Attributes The Implicit cursor attributes returns the information about the execution of an INSERT, DELETE, UPDATE, or SELECT INTO statement. The cursor attribu

Exception handling, set serveroutput on declare a number(5); b n...

set serveroutput on declare a number(5); b number(5); c number(5); begin a:=&a; b:=&b; c:=a/b; dbms_output.put_line(c); exception when zero_d

Declare keyword description in pl sql, DECLARE : This keyword signals t...

DECLARE : This keyword signals the beginning of the declarative section of the PL/SQL block, that contains local declarations. The Items declared locally exist only within the

Transaction control, Transaction Control The Oracle is transaction orie...

Transaction Control The Oracle is transaction oriented; that is, Oracle uses the transactions to make sure the data integrity. The transaction is a sequence of SQL data manip

Triffic light control system, write the program for traffic control system ...

write the program for traffic control system with 10 second, 15 secod, and 20 second delay

%found - implicit cursor attributes, %FOUND Until the SQL data manipul...

%FOUND Until the SQL data manipulation statement is executed, the %FOUND yields NULL. Afterward, the %FOUND yields TRUE, when an INSERT, UPDATE, or DELETE statement affected o

Benefit of the dynamic sql pl sql, Benefit of the dynamic SQL: This pa...

Benefit of the dynamic SQL: This part shows you how to take full benefit of the dynamic SQL and how to keep away from some of the common pitfalls. Passing the Names of Sc

Parameter and keyword description - records, Parameter and Keyword Descript...

Parameter and Keyword Description: record_type_name: This identifies the user-defined type specifier that is used in the subsequent declarations of the records. NOT N

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