EXISTS/NOT EXISTS Predicate Examples | Teradata Vantage - 17.10 - Example: EXISTS with Correlated Subqueries - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - SQL Functions, Expressions, and Predicates

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1145-171K
Language
English (United States)

Select all student names who have registered in at least one class offered by some department.

   SELECT SName, SNo 
   FROM student s 
   WHERE EXISTS 
    (SELECT * 
     FROM department d 
     WHERE EXISTS 
      (SELECT * 
       FROM course c, registration r, class cl 
       WHERE c.Dept=d.Dept 
       AND c.CNo=r.CNo 
       AND s.SNo=r.SNo
       AND r.CNo=cl.CNo 
       AND r.Sec=cl.Sec));

The content of the student table is as follows.

Sname SNo
Helen Chu 1
Alice Clark 2
Kathy Kim 3
Tom Brown 4

The content of the department table is as follows.

Dept DeptName
100 Computer Science
200 Physic
300 Math
400 Science

The content of course table is as follows.

CNo Dept
10 100
11 100
12 200
13 200
14 300

The content of the class table is as follows.

CNo Sec
10 1
11 1
12 1
13 1
14 1

The content of the registration table is as follows.

CNo SNo Sec
10 1 1
10 2 1
11 3 1
12 1 1
13 2 1
14 1 1

The following rows are returned:

   SName              SNo
   -----------        ---
   Helen Chu1           *
   Alice Clark          2
   Kathy Kim            3