What is nested queries explain in details, Database Management System

Assignment Help:

What is Nested Queries explain in details?

Nested Queries - A SELECT query could have subquery(s) in it. While a SELECT query having another SELECT query in it, is known as nested query. A few operations cannot be performed along with single SELECT command or along with join operation. There are some operations that can be performed along with the help of nested queries (also referred to as subqueries). For instance, we want to calculate the second highest salary:

SELECT MAX(SAL) FROM EMP WHERE SAL < (SELECT MAX(SAL) FROM EMP)

Some operations can be performed both through Join and subqueries. The Join operation is costlier in terms of space and time. Thus, the solution based on subqueries is preferred.


Related Discussions:- What is nested queries explain in details

Describe query evaluation engine, Describe Query evaluation engine? Que...

Describe Query evaluation engine? Query Evaluation engine: Vehicle executes low-level instructions obtained through the DML compiler. The Storage Manager Components gives in

BCA, Ask qu. Write a XML with database with book details (Book ID, Title, A...

Ask qu. Write a XML with database with book details (Book ID, Title, Author, subject, published year, language, vendor, and price).estion #Minimum 100 words accepted#

NORRMALIZATION, Home based assignment Consider an ORDER table with the foll...

Home based assignment Consider an ORDER table with the following attributes: • Order Number (ONo),Customer Number (CNo),Customer Name (CNa),Item Number (INo),Unit Price (UP), Quant

Binary relationships, One-to-one relationship: For every 1:1 relationshi...

One-to-one relationship: For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participatio

B2b business uk database, We have a new website where I need someone to 1: ...

We have a new website where I need someone to 1: Inhabit the back end with all the recruitment agencies in the UK. I require someone who is not manually going to do this, but who w

Which database level is closest to the users, Which database level is close...

Which database level is closest to the users? External database level is closest to the users.

What are called jukebox systems, What are called jukebox systems? Jukeb...

What are called jukebox systems? Jukebox systems have a few drives and numerous disks that can be loaded into single of the drives automatically.

State about the tables- DBMS, State about the Tables- DBMS Data is sto...

State about the Tables- DBMS Data is stored in columns and rows (much like a spreadsheet -main difference is how data is organised). Every row in a table is known as a record

What do you mean by an execution plan, What do you mean by an execution pla...

What do you mean by an execution plan? Why is it used? How will you view it? a.) An execution plan can be known as a road map which textually or graphically illustrates the dat

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