Lesson 2.1

Why SQL Data Types Matter

SQL uses column types to decide how values compare, sort, and calculate.

Every column has a type. A column might hold text, numbers, dates, booleans, or missing values. SQL uses those types when it sorts, compares, filters, and calculates.

The difference matters quickly. Sorting product names alphabetically is different from sorting product prices numerically.

Pattern

select column_one, number_column
from table_name
order by number_column desc

Schema · Garden ShopTable · products9 columns · 24 rows

Table · products

One row per product, with price, cost, and inventory levels.

9 columns · 24 rows

product_id intproduct_name textcategory_id intsupplier_id intprice decimalcost decimalquantity_on_hand intreorder_level intdiscontinued bool

Your task

Show each product's product name and price, sorted from the highest price to the lowest. Keep only the first 5 rows.

SQL Workbench

query.sqlgarden_shop · SQL engine loading

⌘↵ to run

Expected answer

Columns: product_name, price.
Rows: 5 products.
The first row should be Fiddle-Leaf Fig at 32.00.

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Next · 2.2 Numbers and calculations →

Lesson

Numbers and Calculations in SQL

Compare, sort, and calculate with numeric values.

Lesson

Why SQL Strings Need Quotes

Filter text values with string literals.

Lesson

Working with Dates and Times in SQL

Compare and sort date values chronologically.

Lesson

Booleans and Flag Columns in SQL

Use true/false columns in filters.

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