SQL Scalar Functions - Complete Beginner Tutorial

Practice Using String Functions

Write a query that extracts the first three characters of a product name and converts them to uppercase.

Expected output: A column showing the first three uppercase letters of each product name.

Hint: Use SUBSTRING() and UPPER() functions together.

Calculate Days Between Dates

Write a query to calculate the number of days between order date and ship date for each order.

Expected output: A column showing the number of days between order and ship dates.

Hint: Use the DATEDIFF() function with the 'day' parameter.

Scalar functions operate on a single value and return a single value, while aggregate functions operate on multiple rows and return a summarized value.

Common scalar functions include UPPER(), LOWER(), ROUND(), ABS(), GETDATE(), and SUBSTRING().

Using scalar functions on indexed columns in WHERE clauses can prevent the database from using the index, leading to slower query performance.