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?

Create student db and retrieve all student name in cs, Create a Student dat...

Create a Student database and Retrieve the names of all students majoring in ‘CS' Consider the following relational database: STUDENT (name, student#, class, major) COURSE (co

ER diagram, #question. acompani datdbase needs to store information about e...

#question. acompani datdbase needs to store information about employees (identified by a social security number,with salary and phone as attributes) and departments (identified by

Non-query optimisations, Part: Recommended (Non-query) Optimisations Thi...

Part: Recommended (Non-query) Optimisations This section entitled "Recommended (non-query) optimisations" should be a brief report containing recommended optimisations you would

Explain five duties of database administrator, Explain five duties of Datab...

Explain five duties of Database Administrator? 1. DBA administers the three stages of the database and, in consultation along with the whole user community, sets up an defin

Explain query tree represent relational algebra expression, How does a quer...

How does a query tree represent a relational algebra expression? Ans: This includes transforming an initial expression (tree) into an equivalent expression (tree) that is

What is database trigger, What is database Trigger? A database trigger ...

What is database Trigger? A database trigger is a PL/SQL block that can explained to automatically execute for insert, update, and delete statements against a table. The trigge

What are the objectives of query processing, What are the objectives of que...

What are the objectives of query processing? Ans: The objectives of query processing is to transform a query written in a high level language into a accurate and efficien

What is difference among mysql_connect and mysql_pconnect, What is differen...

What is difference among mysql_connect and mysql_pconnect? Mysql_connect() opens a new connection to the database while mysql_pconnect() opens persistent connection to the data

Define granularity and hierarchy of granularity of locks, Define granularit...

Define granularity, hierarchy of granularity of locks & multiple granularity locking. Explain the modified two phase locking along with multiple granularity locking. Ans: The s

Discuss the three level architecture of dbms, PRINCIPLES OF DATABASE 1....

PRINCIPLES OF DATABASE 1. State the following terms: a) Database b) Database Management System c) Entity d) Attribute e) Relationship 2. Discuss the Three Level Architecture

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages