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 features relational dbms contribute level of integrity, A well-maintai...

A well-maintained relational DBMS has a high level of data integrity. What features of a relational DBMS contribute towards this level of integrity? Relational DBMS gives high

Explain saving derived attributes to avoid re-computation, Saving Derived A...

Saving Derived Attributes to Avoid Re-computation   As discussed, "redundancy means duplication of exact data". But, if multiple copies of same data are present in the system,

Explain the cascadeless schedule, Explain the Cascadeless Schedule A ca...

Explain the Cascadeless Schedule A cascadeless schedule is one in which for every pair of transactions Ti and Tj like that Tj reads a data item before written by Ti, the commit

#cursor, #what is cursor its uses ? Explain it

#what is cursor its uses ? Explain it

Ldb hierarchy there should exist one get statement, It is mandatory that fo...

It is mandatory that for every table in the LDB hierarchy there should exist one GET statement in the report. False.  It is not essential.

Explain the check clause, Explain the Check Clause The CHECK clause is ...

Explain the Check Clause The CHECK clause is employed to at the end of a CREATE TABLE statement specify table constraints. This is known as table-based constraint because it ap

What is a view, What is a view? A view is a logical view on one or more...

What is a view? A view is a logical view on one or more tables.  A view on one or more tables i.e., the data from a view is not actually physically kept instead being derived f

Queries, Write a query that display ename annual salary and comm from emp t...

Write a query that display ename annual salary and comm from emp table

Appointment systems with sms and voice call feedback, Automated system for ...

Automated system for appointment with sms and call confirmation with service providers and user has to be initiate automatically. After selecting time and date to use service, s

Relational model, A model in database system mostly defines the organisatio...

A model in database system mostly defines the organisation of data or structure and a set of operations on that data. Relational model is a easy model in which database is represen

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