Sql EXISTS CLAUSE

Sql EXISTS CLAUSE
Nikhil
Published on 2021-08-14 14:12:31

EXISTS CLAUSE

Customer Table

Id FirstName LastName
1 Ozgur Ozturk
2 Youssef Medi
3 Henry Tai

Order Table

Id CustomerId Amount
1 2 123.50
2 3 14.80

Get all customers with a least one order

SELECT * FROM Customer WHERE EXISTS (
SELECT * FROM Order WHERE Order.CustomerId=Customer.Id
)

Result

Id FirstName LastName
2 Youssef Medi
3 Henry Tai

Get all customers with no order

SELECT * FROM Customer WHERE NOT EXISTS (
SELECT * FROM Order WHERE Order.CustomerId = Customer.Id
)

Result

Id FirstName LastName
1 Ozgur Ozturk

Purpose

EXISTS, IN and JOIN could sometimes be used for the same result, however, they do not equal:

  • EXISTS should be used to check if a value exists in another table
  • IN should be used for static list
  • JOIN should be used to retrieve data from other(s) table(s)

ATutorialHub Related Guide

Comments (8)

Leave a Comment

Your email address will not be published. Required fields are marked*

User Comments

html tutorial comments

panduranga gupta

2021-07-05 07:03:13

good website for learning and help me a lot

html tutorial comments

raju

2021-09-25 14:58:47

The awsome website i am looking like for a long time, good work atutorialhub team keep doing

html tutorial comments

Shivani

2021-09-01 15:03:56

Learning a lot from the courses present on atutorialhub. The courses are very well explained. Great experience

html tutorial comments

Harshitha

2021-09-10 15:05:45

It is very helpful to students and easy to learn the concepts

html tutorial comments

Sowmya

2021-09-14 15:06:41

Great job Tutorials are easy to understand Please make use of it

html tutorial comments

Zain Khan

2021-09-18 15:07:23

Great content and customized courses.

html tutorial comments

Rudrakshi Bhatt

2021-09-09 15:08:10

Well structured coursed and explained really well!

html tutorial comments

Pavana Somashekar

2021-09-11 15:09:08

Good platform for beginners and learn a lot on this website