SQL_T3

Which of the following statements contains an error?

• Select * from emp where empid = 10003;
• Select empid from emp where empid = 10006;
• Select empid from emp;
• Select empid where empid = 1009 and lastname = ‘GELLER’;

Which logical operator in PostgreSQL negates a condition and returns true if the condition is false?

• AND
• OR
• NOT
• JOIN

What does the pattern 'j%' in the expression FirstName LIKE 'j%' represent?

• Records whose FirstName starts with 'j'
• Records whose FirstName contains 'j' or 'J' at any position
• Records whose FirstName ends with 'j' or 'J'
• Records whose FirstName is not 'j' or 'J'

If you don’t specify ASC or DESC after a SQL ORDER BY clause, the following is used by default

• ASC
• DESC
• There is no default value
• None of the mentioned

The ORDER BY clause in PostgreSQL is used to:

• Filter rows based on specific conditions.
• Group rows based on one or more columns.
• Sort the result set based on one or more columns.
• Specify the order of columns in the result set.

With SQL, how can you return all the records from a table named “Persons” sorted descending by “FirstName”?

• SELECT * FROM Persons SORT BY ‘FirstName’ DESC;
• SELECT * FROM Persons ORDER FirstName DESC;
• SELECT * FROM Persons SORT ‘FirstName’ DESC;
• SELECT * FROM Persons ORDER BY FirstName DESC;

What is the significance of “ORDER BY” in the following PostgreSQL statement? SELECT emp_id, fname, lname FROM person ORDER BY emp_id;

• Data of emp_id will be sorted in ascending order
• Data of emp_id will be sorted in descending order
• Data will not be sorted
• None of these

Which clause should be used when we can not use aggregate function with WHERE?

• WHERE
• HAVING
• RESTRICT
• GROUP BY

We can test for the nonexistence of tuples in a subquery by using the            .

• Not exist
• Not exists
• Exist
• Exists

Which of the following statements are TRUE regarding subqueries?

• A subquery can retrieve zero or more rows
• A subquery can appear on either side of a comparison operator
• None of the above
• Both A and B