Interview MasterSQL Learning Hub
SELECT Statement
SELECT Statement
Learn how to use the SELECT statement to retrieve data from database tables
Understanding the SQL SELECT Statement
The SELECT statement is the most fundamental SQL command. It retrieves specific columns of data from one or more tables in a database. If you're new to SQL, this is the perfect place to start your journey.
Basic Syntax
Common SQL SELECT Interview Questions
- How do you select all columns from a table?
- How do you select specific columns from a table?
- How can you rename columns in the result set?
- What is the difference between SELECT and SELECT DISTINCT?
SQL SELECT Statement Variations
Selecting All Columns
Use the asterisk (*) to select all columns from a table.
Note: While convenient for exploration and learning, using SELECT * in production code is generally discouraged.
Selecting Specific Columns
Specify the exact columns you want to retrieve.
SQL SELECT DISTINCT
Use DISTINCT to remove duplicate values from that column.
Column Aliases in SQL
Use the AS keyword to give columns more readable names in the result set. Aliases can be written with or without quotes, but quotes are required in certain cases:
When to Use Quotes in Aliases
- Use quotes when the alias contains spaces
- Use quotes when the alias contains special characters
- Use quotes when the alias matches SQL keywords
- Simple aliases (letters, numbers, underscores) don't need quotes
Practical SQL SELECT Examples
Example 1: Retrieve interaction information from the Interactions table
This example shows how to retrieve basic interaction information from the Interactions table:
Example 2: Retrieve video information from the Videos table
This example shows how to retrieve video information:
Best Practices for SQL SELECT Statements
1. Be Explicit About Columns
Always specify the columns you need instead of using SELECT *. This improves performance and makes your code more maintainable.
2. Use Clear Column Aliases
When renaming columns, provide meaningful aliases to make your results more readable.
3. Consider Column Order
List columns in a logical order (e.g., primary key first, then important identifiers, followed by details) to improve readability.
Test Your Knowledge
Take a quick quiz to reinforce what you've learned about SELECT Statement
Ready for hands-on SQL practice?
We have 200+ questions on real companies and real products.
