Introduction to SQL
Which of the following query finds the name of the sailors who have reserved at least two boats?

SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND r1.sid = r2.sid AND r1.bid <> r2.bid
SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND r1.sid = r2.sid AND r1.bid ≠ r2.bid
SELECT DISTINCT s.sname FROM sailors s, reserves r1, reserves r2 WHERE s.sid = r1.sid AND COUNT(r1.bid) > r2.bid
All of these

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Introduction to SQL
What is a view?

A view is a special stored procedure executed when certain event occurs.
A view is a virtual table which results of executing a pre-compiled query. A view is not part of the physical database schema, while the regular tables are.
None of these
A view is a database diagram.

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Introduction to SQL
Which of the following query is correct for using comparison operators in SQL?

SELECT name, course_name FROM student WHERE age>50 and age <80;
None of these
SELECT name, course_name FROM student WHERE age>50 and <80;
SELECT name, course_name FROM student WHERE age>50 and WHERE age<80;

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Introduction to SQL
To define what columns should be displayed in an SQL SELECT statement:

use FROM to name the source table(s) and list the columns to be shown after SELECT.
use USING to name the source table(s) and list the columns to be shown after SELECT.
use USING to name the source table(s) and list the columns to be shown after WHER
use SELECT to name the source table(s) and list the columns to be shown after USING.

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