Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Creating a Table Syantax: CREATE TABLE ENROLMENT (StudentId SID, Name VARCHAR (30) NOT NULL, CourseId CID, PRIMARY KEY (StudentId, CourseId)) ; Explan
Operator Precedence The operations within an expression are completed in a particular order depending on their precedence (priority). The table shows the default order of the op
Count Operator in SQL Example: Counting the students who have scored more than 50 in some exam (SELECT COUNT (*) FROM (SELECT DISTINCT StudentId FROM EXAM_MARK WHE
Overview of control structures According to the structure theorem, any computer program can be written by using the basic control structures as shown in figure below. They can b
Understanding Nested Tables Within the database, the nested tables can be considered as one-column database tables. The Oracle stores the rows of a nested table in no specific o
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
Effects of NULL Operator As a general rule-but not a universal one-if NULL is an argument to an invocation of a system-defined read-only operator, then NULL is the result of t
Number Types The Number types permit you to store the numeric data (real numbers, integers, and floating-point numbers), show quantities, and do computations. BINARY_INTEG
Procedural Constraint Enforcement (Triggers) SQL has an alternative method of addressing database integrity, involving event-driven procedural code. The special procedures th
Autonomous versus Nested Transactions Though an autonomous transaction is started by the other transaction, it is not a nested transaction for the reasons shown below: (i)
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd