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

What are decision support systems, (a) What are decision support systems, a...

(a) What are decision support systems, and what role do they play in the business environment? (b) Data warehousing is defined as "a subject-oriented, integrated, non-volatile c

Create a sql database, The requirements as follows: Create a folder call...

The requirements as follows: Create a folder called "SECURITY" on the server and upload all your project files to that folder. Please note, the "SECURITY" folder is NOT to be IN

Unnest operator in sql, UNNEST operator in SQL The inverse operator of...

UNNEST operator in SQL The inverse operator of GROUP is UNGROUP. SQL has an operator, UNNEST, that can be used for similar purposes, but its method of invocation is somewhat p

Between and not between operator in sql, BETWEEN and NOT BETWEEN Operator i...

BETWEEN and NOT BETWEEN Operator in SQL Example: Restricting exam marks to between 0 and 100 CREATE ASSERTION Marks_between_0_and_100 CHECK (NOT EXISTS (SELECT * FROM

%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

Tautologies, Tautologies: Above given table allows us to read the trut...

Tautologies: Above given table allows us to read the truth of the connectives in the next manner. Just expect we are looking at row three. It means this says that, if there P

Application to export excel data to mssql server table, Application to Expo...

Application to Export Excel Data to MSSQL Server table I am having a table available in excel format and features the subsequent: - Some text is in Arabic (e.g. UTF-8 encodin

Row operators - sql operators, Row Operators The Row operators return ...

Row Operators The Row operators return or reference the particular rows. ALL retains the duplicate rows in the result of a query or in an aggregate expression. The DISTINCT el

When or then key constraints, WHEN or THEN Key Constraints Suppose a t...

WHEN or THEN Key Constraints Suppose a table has two columns representing a period of time throughout which the information conveyed by the other columns is recorded as having

Sql database, SQL Database: So, an SQL database is one whose symbols a...

SQL Database: So, an SQL database is one whose symbols are organized into a collection of tables. Now, shows an SQL table as the current value of an SQL variable, ENROLMENT, b

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