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Lesson 1.3 · garden_shop
Lesson 1.3

Tables, Rows, and Columns in SQL

Tables organize data into columns, and each row is one record.

A table has a name, like customers. Columns describe the fields available in that table, like first_name or state.

Rows are the records inside the table. In the Garden Shop dataset, each row in customers represents one customer.

Read a table before querying it

Before writing a report query, inspect the table name, the column names, and a few sample rows. That quick scan tells you what each row represents, which columns are identifiers, and which columns are useful for filtering, sorting, or grouping.

Pattern 
select count(*) as row_count
from table_name
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

Count how many rows are in the customers table. Name the output column customer_count.

·

Run your query to inspect the result.

Expected answer
  • Columns: customer_count.
  • Rows: 1 summary row.
  • The customer_count value should be 20.
Next · 1.4 Meet the workbench →

Related

Reference
SQL SELECT Syntax

Clause order and the shape of a SELECT query.

Cheatsheet
SQL Query Basics Cheatsheet

SELECT, WHERE, ORDER BY, and LIMIT at a glance.

Error
Fix “Column Not Found” When Filtering on a SQL Alias

WHERE is evaluated before SELECT aliases exist.

Error
Fix “Syntax Error at or Near” in SQL

The parser stopped at the first word it could not use.

Error
Fix “Referenced Column Not Found” in SQL

No table in the FROM clause has that column.

Lesson
What Is SQL?

Understand tables, rows, columns, and queries.