Lesson 7.3

Cleaning and Reshaping Text in SQL

Real text data needs reshaping. Functions like lower, trim, left, and || build clean, consistent values.

Text rarely arrives in exactly the shape you need. SQL gives you small building blocks to fix that: lower() and upper() change case, trim() removes stray spaces, and left() grabs the first few characters.

The || operator glues strings together. Chain these and you can build a clean, consistent value out of messy parts.

Pattern

select product_id,
       upper(trim(product_name)) as product_name_clean
from products

Syntax reference

Need syntax details? See the SQL string functions reference

Schema · Garden Shop Table · customers 9 columns · 20 rows

Table · customers

One row per customer. Some customers have no phone on file.

9 columns · 20 rows

customer_id int first_name text last_name text email text phone text city text state text signup_date date is_active bool

Your task

Generate a login handle for each customer: the first letter of their first name joined to their full last name, all in lowercase. Return customer_id, first_name, last_name, and the handle as login. Sort by customer_id.