What is null described testing for null in sql?, Database Management System

Assignment Help:

What is NULL? Give an example to described testing for NULL in SQL?

The NULL SQL keyword is used to represent either a missing value or a value which is not applicable in a relational table. Consider there is a relation:

Person(id, name, address, phone)
Now to search ids and names of person who do not have a phone is:
Select id, name
from Person
where phone is null


Related Discussions:- What is null described testing for null in sql?

Write query to insert data in student table, Consider student (std_id, std_...

Consider student (std_id, std_name, date_of_birth, phone, dept_name). Put the data for a student with student id200, name arun, birth date 1 February, 1985, phone number (01110 328

List any eight applications of dbms, List any eight applications of DBMS. ...

List any eight applications of DBMS. a) Universities b) Airlines c) Banking d) Credit card transactions e) Tele communication f) Sales g)Finance h) Manufac

Describe the advantage of state chart diagram, Describe the advantage of St...

Describe the advantage of State chart Diagram A state chart represents a state machine, emphasizing flow of control from one state to other. A state machine is a behaviour whi

Managing databases, Code an Oracle Database trigger to enforce the constrai...

Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department.

Differentiate between a subquery and a join, Differentiate between a subque...

Differentiate between a subquery and a join If we need to acquire information from one or more tables after that either subquery or join can be used. If the columns which are t

Hashed file organisation, Hashed File Organisation Hashing is the most ...

Hashed File Organisation Hashing is the most common form of purely random access to a database or file. It is also used to access columns that do not have an index as an optimi

Key constraint - relational constraints, This constraint shows that the key...

This constraint shows that the key attribute value in each tuple must be unique, i.e., no two tuples have the similar value for the key attribute. This is because the value of the

What is conceptual schema, What is Conceptual Schema? Conceptual Schema...

What is Conceptual Schema? Conceptual Schema - Conceptual schema elaborates the structure of the overall database for a community of users. It hides the details of physical sto

What does the cardinality ratio specify, What does the cardinality ratio sp...

What does the cardinality ratio specify? Mapping cardinalities or cardinality ratios state the number of entities to which another entity can be associated. Mapping cardinaliti

Distributed query and transaction processing, a.  Construct a query around ...

a.  Construct a query around any one of the functional divisions you made in 4a such that if executed in the distributed design of 4 would require reconstruction of at least two ho

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