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?

Differance between internal and external schema, Differance between interna...

Differance between internal and external schema? Internal and external schema: Internal Schema • Describes the physical storage structure • Uses a physical data model External

Define what Immediate database modification technique uses, Define what Imm...

Define what Immediate database modification technique uses?  Ans: Both undo and redo.

Explain the functional mode with help of an example, Explain the Functional...

Explain the Functional Mode with help of an example. Functional Model  The functional model shows a computation and functional derivation of data values in it without ind

Types of online analytical processing tools, Describe the various types of ...

Describe the various types of Online Analytical Processing (OLAP) tools and briefly discuss how the support common analytical operations.

Describe all integrity constraints which are violated, Consider the two rel...

Consider the two relations given below Given that A is the primary key of R, D is the primary key of S and there is a referential integrity among S.A and R.A, discuss all

What are axioms, What are axioms? Axioms or rules of inference give a s...

What are axioms? Axioms or rules of inference give a simpler technique for reasoning about

Hierarchical data representation model, Examples:- Hierarchical Model: I...

Examples:- Hierarchical Model: It tells data as and relationships by hierarchy of data values. Figure illustrates an example of hierarchical model. Now a day's these models are

Two types of blocks in the fixed -length representation, What are the two t...

What are the two types of blocks in the fixed -length representation? Define them. Anchor block: Have the first record of a chain. Overflow block: Have the records other tha

One-to-many relationship, For each 1: n relationship type R involving two e...

For each 1: n relationship type R involving two entities E1 and E2, we recognize the entity type (say E1) at the n-side of the relationship type R and contain primary key of the en

Define single valued and multivalued attributes, Define single valued and m...

Define single valued and multivalued attributes.  Single valued attributes: attributes with a single value for a particular entity are known as single valued attributes.   M

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