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?

What is transaction, What is transaction? Transaction is a unit of prog...

What is transaction? Transaction is a unit of program implementation that accesses and possibly updated several data items.

Demonstrate the design of associations, Demonstrate the Design of associati...

Demonstrate the Design of associations During object design phase we must design a strategy to implement associations. Association may be unidirectional or bi-directional. Wha

Define the term- control as state within program, Control as State within P...

Control as State within Program 1. The term control exactly means to check effect of input within a program. For illustration, in Figure, after the ATM card is inserted (a

Define query processing, Define Query Processing Query processing is th...

Define Query Processing Query processing is the process of selecting the best plan or strategy to be employed in responding to a database request. The plan is then executed to

Ideal data dictionary, An ideal data dictionary should have everything a DB...

An ideal data dictionary should have everything a DBA wants to know about the database. 1 Conceptual, External, and internal database descriptions. 2. Descriptions of attr

Normalization, a project based on normalization with first, second and thir...

a project based on normalization with first, second and third normalization. There need to be a diagram also

Client server databases, Client Server Databases- The concept behind the C...

Client Server Databases- The concept behind the Client/Server systems is simultaneous, cooperative processing. It is an approach that presents a one systems view from a user's vie

Creating database for library, i need help with creating database system fo...

i need help with creating database system for a library

Query to delete constraint from alter table, A constraint named less_than_2...

A constraint named less_than_20 was defined on the field date_of_birth of table student. Delete this constraint. ALTER TABLE student DROP CONSTRAINT less_than_20;

What is meant by the degree of relationship set, What is meant by the degre...

What is meant by the degree of relationship set? The degree of relationship type is the number of participating entity types.

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages