SQL
1 Introduction to SQL
1.1 Overview of SQL
1.2 History and Evolution of SQL
1.3 Importance of SQL in Data Management
2 SQL Basics
2.1 SQL Syntax and Structure
2.2 Data Types in SQL
2.3 SQL Statements: SELECT, INSERT, UPDATE, DELETE
2.4 SQL Clauses: WHERE, ORDER BY, GROUP BY, HAVING
3 Working with Databases
3.1 Creating and Managing Databases
3.2 Database Design Principles
3.3 Normalization in Database Design
3.4 Denormalization for Performance
4 Tables and Relationships
4.1 Creating and Modifying Tables
4.2 Primary and Foreign Keys
4.3 Relationships: One-to-One, One-to-Many, Many-to-Many
4.4 Joins: INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN
5 Advanced SQL Queries
5.1 Subqueries and Nested Queries
5.2 Common Table Expressions (CTEs)
5.3 Window Functions
5.4 Pivoting and Unpivoting Data
6 Data Manipulation and Aggregation
6.1 Aggregate Functions: SUM, COUNT, AVG, MIN, MAX
6.2 Grouping and Filtering Aggregated Data
6.3 Handling NULL Values
6.4 Working with Dates and Times
7 Indexing and Performance Optimization
7.1 Introduction to Indexes
7.2 Types of Indexes: Clustered, Non-Clustered, Composite
7.3 Indexing Strategies for Performance
7.4 Query Optimization Techniques
8 Transactions and Concurrency
8.1 Introduction to Transactions
8.2 ACID Properties
8.3 Transaction Isolation Levels
8.4 Handling Deadlocks and Concurrency Issues
9 Stored Procedures and Functions
9.1 Creating and Executing Stored Procedures
9.2 User-Defined Functions
9.3 Control Structures in Stored Procedures
9.4 Error Handling in Stored Procedures
10 Triggers and Events
10.1 Introduction to Triggers
10.2 Types of Triggers: BEFORE, AFTER, INSTEAD OF
10.3 Creating and Managing Triggers
10.4 Event Scheduling in SQL
11 Views and Materialized Views
11.1 Creating and Managing Views
11.2 Uses and Benefits of Views
11.3 Materialized Views and Their Use Cases
11.4 Updating and Refreshing Views
12 Security and Access Control
12.1 User Authentication and Authorization
12.2 Role-Based Access Control
12.3 Granting and Revoking Privileges
12.4 Securing Sensitive Data
13 SQL Best Practices and Standards
13.1 Writing Efficient SQL Queries
13.2 Naming Conventions and Standards
13.3 Documentation and Code Comments
13.4 Version Control for SQL Scripts
14 SQL in Real-World Applications
14.1 Integrating SQL with Programming Languages
14.2 SQL in Data Warehousing
14.3 SQL in Big Data Environments
14.4 SQL in Cloud Databases
15 Exam Preparation
15.1 Overview of the Exam Structure
15.2 Sample Questions and Practice Tests
15.3 Time Management Strategies
15.4 Review and Revision Techniques
SQL Basics: SELECT and FROM

SQL Basics: SELECT and FROM

1. SELECT Statement

The SELECT statement is the most fundamental command in SQL. It is used to retrieve data from a database. The data returned is stored in a result table, often referred to as the result-set.

Imagine you have a library of books, and you want to list all the titles. The SELECT statement is like asking the librarian to give you a list of all the book titles.

Example:

SELECT title FROM books;

In this example, the SELECT statement retrieves the title column from the books table.

2. FROM Clause

The FROM clause specifies the table from which to retrieve the data. It is always used in conjunction with the SELECT statement.

Continuing with the library analogy, the FROM clause is like specifying which shelf or section of the library you want to look at.

Example:

SELECT title FROM books;

Here, the FROM clause indicates that the data should be retrieved from the books table.

Combining SELECT and FROM

When you combine the SELECT statement with the FROM clause, you can effectively query the database to get the specific information you need.

Example:

SELECT title, author FROM books WHERE genre = 'Science Fiction';

In this example, the query retrieves the title and author columns from the books table where the genre is 'Science Fiction'.