SQL Sorting and Limiting Results 3

Question 1

How are NULL values typically sorted in PostgreSQL ascending order by default?

Accepted Answer

NULLs appear last

Answer

NULLs appear first

Answer

NULLs are excluded

Answer

NULLs cause an error

Question 2

Which clause forces NULL values to appear first in PostgreSQL?

Accepted Answer

ORDER BY col NULLS FIRST

Answer

ORDER BY col NULL TOP

Answer

ORDER BY NULL col

Answer

ORDER BY col ASC NULLS

Question 3

Can you ORDER BY a column that is not in the SELECT list?

Accepted Answer

Yes, in most databases

Answer

No, never

Answer

Only if it is a primary key

Answer

Only with GROUP BY

Question 4

Which standard SQL clause limits rows using FETCH?

Accepted Answer

FETCH FIRST n ROWS ONLY

Answer

FETCH TOP n ROWS

Answer

FETCH LIMIT n

Answer

FETCH n ROWS LIMIT

Question 5

What does ORDER BY salary DESC, hire_date ASC do?

Accepted Answer

Highest salary first, ties broken by earliest hire date

Answer

Lowest salary first, ties by latest hire

Answer

Sorts only by salary

Answer

Sorts only by hire date

Question 6

In MySQL, what does LIMIT 5 with no OFFSET return?

Accepted Answer

The first 5 rows

Answer

The last 5 rows

Answer

Rows 5 through 10

Answer

5 random rows

Question 7

Which is valid MySQL shorthand for OFFSET 20 LIMIT 10?

Accepted Answer

LIMIT 20, 10

Answer

LIMIT 10, 20

Answer

LIMIT 20 OFFSET 10

Answer

OFFSET 20, 10