SQL

These concepts require a deeper understanding of SQL and its ecosystem. They are necessary for optimizing performance, managing complex queries, ensuring data integrity, and leveraging advanced features for high-level query design and development.

1. Advanced Joins and Set Operations

   • Activities involved: Writing advanced joins (CROSS JOIN, SELF JOIN) and set operations (UNION, INTERSECT, EXCEPT).

   • Reason: Advanced joins and set operations are necessary for performing complex data manipulations and combining results from multiple queries.

   • Example Task: Write a query that uses a UNION to combine results from two different queries.

2. Stored Procedures and Functions

   • Activities involved: Creating and using stored procedures and user-defined functions.

   • Reason: Stored procedures and functions encapsulate reusable logic and improve performance by reducing client-server round trips.

   • Example Task: Create a stored procedure that performs multiple operations and a user-defined function that performs a calculation.

3. Advanced Subqueries

   • Activities involved: Writing correlated subqueries and using subqueries in advanced scenarios.

   • Reason: Advanced subqueries provide powerful ways to solve complex querying needs.

   • Example Task: Write a correlated subquery that references columns from the outer query.

4. Performance Tuning and Query Optimization

   • Activities involved: Analyzing and optimizing query performance, using execution plans.

   • Reason: Performance tuning is critical for ensuring efficient and responsive database operations.

   • Example Task: Use an execution plan to identify bottlenecks in a query and optimize it for better performance.

5. Common Table Expressions (CTEs)

   • Activities involved: Using CTEs for complex queries and recursive queries.

   • Reason: CTEs simplify complex query writing and improve readability.

   • Example Task: Write a recursive CTE to query hierarchical data.

6. Window Functions

   • Activities involved: Using window functions like ROW_NUMBER, RANK, DENSE_RANK, LEAD, LAG.

   • Reason: Window functions provide powerful tools for performing calculations across rows related to the current row.

   • Example Task: Write a query that uses ROW_NUMBER to assign row numbers within partitions of a result set.

7. Data Integrity and Constraints

   • Activities involved: Implementing and managing constraints (PRIMARY KEY, FOREIGN KEY, UNIQUE, CHECK).

   • Reason: Constraints ensure data integrity and enforce business rules at the database level.

   • Example Task: Add constraints to a table and demonstrate how they enforce data integrity during insertions and updates.

8. Prepared Statements

   • Activities involved: Using PREPARE, EXECUTE, and DEALLOCATE PREPARE Statements

   • Reason: Prepared statements are needed to efficiently handle dynamic queries and evaluate strings while ensuring data is accurately parameterized, reducing the risk of SQL injection.

   • Example Task: Create a prepared statement by using a string literal to supply the text of the statement or user variable.