# Select and Filter Data - SELECT Statement
# Database Basics Refresher
Databases exist to help us store and manage large amounts of information in an organized way. In SQL this data is organized into tables consisting of rows and columns. Each table in a database represents a different entity, such as customers, products, or orders. The rows in the table represent individual records, and the columns represent the attributes of these entities.
# Example Table: Customers
| CustomerID | FirstName | LastName | |
|---|---|---|---|
| 1 | John | Doe | johndoe@email.com |
| 2 | Jane | Smith | janesmith@email.com |
| 3 | Alex | Johnson | alexj@email.com |
# SELECT Statements
The SELECT statement is used to retrieve data from a database. It allows you to specify exactly which data you want to fetch from a table.
# Basic SELECT Syntax
| |
# Selecting Specific Columns
To retrieve specific columns from a table, list the column names separated by commas. For example the query:
| |
# Expected Output:
| FirstName | LastName |
|---|---|
| John | Doe |
| Jane | Smith |
| Alex | Johnson |
# Selecting All Columns
To select all columns from a table, use the asterisk * symbol:
| |
This query will result in the entire Customers table being displayed.
# Practice Questions
- Select only the contact’s name and age columns from the Customer table.
# Lessons
- SQL - W2 Select and Filter Data - Introduction
- SQL - W2 Select and Filter Data - Creating a Database
- SQL - W2 Select and Filter Data - Running Scripts
- SQL - W2 Select and Filter Data - SELECT Statement
- Next: SQL - W2 Select and Filter Data - WHERE Clause and Comparison Operators
- SQL - W2 Select and Filter Data - Logical Operators
- SQL - W2 Select and Filter Data - ORDER BY
- SQL - W2 Select and Filter Data - SQL Comments
- SQL - W2 Select and Filter Data - Note on Semicolons
- SQL - W2 Select and Filter Data - Practice Assignment