SQL

These concepts cover the fundamental syntax and basic features of SQL. They are necessary for writing simple SQL queries and understanding the core structure and flow of database operations.

1. Introduction to SQL

   • Activities involved: Setting up a database environment and understanding SQL’s purpose and use cases.

   • Reason: Fundamental setup and understanding are necessary to start writing SQL queries.

   • Example Task: Install a relational database (e.g., MySQL, PostgreSQL) and connect to it using a SQL client.

2. Basic SQL Queries

   • Activities involved: Writing SELECT statements, filtering results with WHERE clauses.

   • Reason: Basic queries are essential for retrieving data from a database.

   • Example Task: Write a query to select specific columns from a table and filter the results using a WHERE clause.

3. Data Definition Language (DDL)

   • Activities involved: Creating, altering, and dropping tables using CREATE, ALTER, DROP.

   • Reason: DDL commands define the structure of the database.

   • Example Task: Create a new table with columns for different data types.

4. Data Manipulation Language (DML)

   • Activities involved: Inserting, updating, and deleting data using INSERT, UPDATE, DELETE.

   • Reason: DML commands manage the data within the database.

   • Example Task: Insert new records into a table, update existing records, and delete records based on a condition.

5. Basic Functions and Expressions

   • Activities involved: Using aggregate functions like COUNT, SUM, AVG, MIN, MAX.

   • Reason: Functions and expressions enhance the ability to perform calculations and manipulate data within queries.

   • Example Task: Write a query that calculates the average value of a numeric column and counts the number of rows.

6. Sorting and Limiting Results

   • Activities involved: Sorting results using ORDER BY, limiting the number of results with LIMIT.

   • Reason: Sorting and limiting results are common operations for managing query output.

   • Example Task: Write a query to retrieve the top 5 highest values in a column.

7. Joins

   • Activities involved: Writing queries using different types of joins (INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN).

   • Reason: Joins are crucial for combining data from multiple tables based on related columns.

   • Example Task: Write a query to join two tables and retrieve related data from both tables.