Introduction to SQL
What does the following query find?(SELECT DISTINCT r.sidFROM boats b, reserves rWHERE b.bid = r.bidAND b.color = 'red')MINUS(SELECT DISTINCT r.sidFROM boats b, reserves rWHERE b.bid = r.bidAND b.color = 'green')

None of These
Find the sailor Ids of atmost one sailor who have reserved red boats but not green boats
Find the sailor IDs of all sailors who have reserved red boats but not green boats
Find the sailor IDs of at least one sailor who have reserved red boats but not green boats

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

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Introduction to SQL
The HAVING clause does which of the following?

Acts like a WHERE clause but is used for rows rather than columns.
Acts like a WHERE clause but is used for columns rather than groups.
Acts like a WHERE clause but is used for groups rather than rows.
Acts EXACTLY like a WHERE clause.

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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 database diagram.
None of these
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.

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