GREATEST and LEAST functions in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the greatest value among three numbers.

PostgreSQL

SELECT GREATEST([1]) AS max_value;

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

A5, 10, 3

B5 10 3

C'5', '10', '3'

D(5, 10, 3)

Attempts:

3 left

💡 Hint

Common Mistakes

Passing numbers without commas

Using quotes around numbers making them strings

Passing a tuple instead of separate arguments

The GREATEST function takes multiple arguments separated by commas and returns the largest value. So, 5, 10, 3 is the correct way to pass the numbers.

2fill in blank

medium

Complete the code to find the least value among columns price1, price2, and price3 in the products table.

PostgreSQL

SELECT LEAST([1]) AS min_price FROM products;

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

Aprice1 price2 price3

Bprice1, price2, price3

C'price1', 'price2', 'price3'

D(price1, price2, price3)

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting commas between column names

Putting column names in quotes

Using parentheses around the list as a single argument

The LEAST function compares multiple columns or values separated by commas and returns the smallest one. So, the columns must be separated by commas without quotes.

3fill in blank

hard

Fix the error in the code to correctly find the greatest value between two columns colA and colB.

PostgreSQL

SELECT GREATEST([1]) AS max_val FROM data;

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

A(colA, colB)

BcolA colB

CcolA, colB

D'colA', 'colB'

Attempts:

3 left

💡 Hint

Common Mistakes

Missing commas between column names

Using quotes around column names

Passing columns as a tuple

The GREATEST function requires its arguments to be separated by commas without quotes or parentheses around them as a single argument. So, colA, colB is correct.

4fill in blank

hard

Fill both blanks to find the least value between two columns and rename the output as lowest.

PostgreSQL

SELECT LEAST([1]) AS [2] FROM sales;

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

Acost, price

Bmin_value

Clowest

Dcost price

Attempts:

3 left

💡 Hint

Common Mistakes

Not separating columns with commas

Using invalid alias names or quotes around alias

Putting spaces instead of commas between columns

The LEAST function needs the columns separated by commas, and the alias for the output can be any valid name like lowest.

5fill in blank

hard

Fill all three blanks to select the greatest value between col1 and col2, rename it as max_col, and filter rows where the greatest value is greater than 100.

PostgreSQL

SELECT GREATEST([1]) AS [2] FROM records WHERE GREATEST([3]) > 100;

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

Acol1, col2

Bmax_col

Dcol1 col2

Attempts:

3 left

💡 Hint

Common Mistakes

Using spaces instead of commas between columns

Using different column lists in SELECT and WHERE

Using quotes around alias or columns

The GREATEST function requires columns separated by commas. The alias max_col names the output. The WHERE clause uses the same columns separated by commas to filter rows.