SQL Sorting and Limiting Results 5

Question 1

What does ORDER BY RANDOM() do in PostgreSQL?

Accepted Answer

Returns rows in random order

Answer

Sorts numerically

Answer

Throws an error

Answer

Sorts by primary key

Question 2

Which gets a single random row efficiently in MySQL?

Accepted Answer

ORDER BY RAND() LIMIT 1

Answer

ORDER BY RANDOM() LIMIT 1

Answer

SELECT RANDOM ROW

Answer

LIMIT RAND() 1

Question 3

When sorting strings of numbers stored as text, what happens?

Accepted Answer

They sort lexicographically (e.g., '10' before '2')

Answer

They sort numerically

Answer

They cause an error

Answer

They are ignored

Question 4

What does ORDER BY 1 DESC do?

Accepted Answer

Sorts by the first SELECT column descending

Answer

Sorts a column named '1'

Answer

Returns 1 row descending

Answer

Reverses all columns

Question 5

Which is generally faster than LIMIT/OFFSET for deep pagination?

Accepted Answer

Keyset (seek) pagination using WHERE on a sorted key

Answer

Larger OFFSET values

Answer

Removing ORDER BY

Answer

Using SELECT *

Question 6

Does adding LIMIT change the total count of matching rows in the table?

Accepted Answer

No, it only limits rows returned

Answer

Yes, it deletes extra rows

Answer

Yes, it caps the table size

Answer

It depends on indexes

Question 7

To find the second-highest salary, which approach works?

Accepted Answer

ORDER BY salary DESC LIMIT 1 OFFSET 1

Answer

ORDER BY salary DESC LIMIT 2

Answer

ORDER BY salary ASC LIMIT 1

Answer

LIMIT 1 OFFSET 2