Why built-in functions matter in SQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the current date using a built-in SQL function.

SQL

SELECT [1];

Drag options to blanks, or click blank then click option'

ACURRENT_DATE

BNOW

CGETDATE

DTODAY

Attempts:

3 left

💡 Hint

Common Mistakes

Using NOW() returns date and time, not just the date.

GETDATE() is specific to some SQL dialects like SQL Server.

TODAY() is not a standard SQL function.

The CURRENT_DATE function returns the current date in SQL.

2fill in blank

medium

Complete the code to count the number of rows in the 'employees' table using a built-in function.

SQL

SELECT [1](*) FROM employees;

Drag options to blanks, or click blank then click option'

ASUM

BNUMBER

CTOTAL

DCOUNT

Attempts:

3 left

💡 Hint

Common Mistakes

Using SUM(*) is invalid because SUM expects a numeric column.

TOTAL is not a standard SQL aggregate function.

NUMBER is not a SQL function.

The COUNT(*) function counts all rows in a table.

3fill in blank

hard

Fix the error in the code to convert the 'name' column to uppercase using a built-in function.

SQL

SELECT [1](name) FROM users;

Drag options to blanks, or click blank then click option'

Alower

Bcapitalize

CUPPER

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using lower() converts text to lowercase, not uppercase.

capitalize and title are not standard SQL functions.

The UPPER() function converts text to uppercase in SQL.

4fill in blank

hard

Fill both blanks to select the average salary and round it to 2 decimal places.

SQL

SELECT ROUND(AVG([1]), [2]) FROM employees;

Drag options to blanks, or click blank then click option'

Asalary

B2

C3

Dbonus

Attempts:

3 left

💡 Hint

Common Mistakes

Using bonus instead of salary changes the meaning.

Rounding to 3 decimals when 2 is requested.

Use AVG(salary) to get the average salary and ROUND(..., 2) to round to 2 decimals.

5fill in blank

hard

Fill all three blanks to select the maximum age, minimum age, and calculate the age difference in the 'people' table.

SQL

SELECT MAX([1]) AS max_age, MIN([2]) AS min_age, MAX(age) - MIN([3]) AS age_diff FROM people;

Drag options to blanks, or click blank then click option'

Aage

Bbirth_year

Dheight

Attempts:

3 left

💡 Hint

Common Mistakes

Using birth_year or height instead of age causes wrong results.

Mixing different columns in the calculation.

Use age column for MAX and MIN functions to find max and min age, then subtract to get difference.