SQL Functions

Question 1

Does BETWEEN include the min and max values in the range?

Answer 1

YES

Question 1

How IIF function works?

Answer 1

It works like a ternary
e.g.
IIF(carA > carB, “Car a is bigger”, “Car b is bigger”)

Question 2

Which function is used to get no duplicate records?

Answer 2

DISTINCT
e.g
SELECT DISTINCT previous_company
FROM employees;

Question 3

What is the difference between “%” and “_” operators?

Answer 3

• ”%” matches zero or more characters
• “_” matches a single character

Question 4

What is the default ORDER BY?

Answer 4

Ascending (ASC)

Question 5

What is an aggregation?

Answer 5

An “aggregation” is a single value that’s derived by combining several other values.

Question 6

When to use the “HAVING” clause?

Answer 6

When we need to filter the results of a GROUP BY query even further.

Question 7

What’s the difference between WHERE and HAVING?

Answer 7

• A WHERE condition is applied to all the data in a query before it’s grouped by a GROUP BY clause.
• A HAVING condition is only applied to the grouped rows that are returned after a GROUP BY is applied.