SQL DAY 4

SQL Day 4: Advanced Logic, Data Migration & Stored Procedures Welcome back to Day 4 of our SQL series! In everyday data engineering operations, writing a query is just the beginning. Ensuring your code is reusable, your data migrations are safe, and your logic can elegantly handle missing data is what sets professionals apart. Today, we move beyond simple SELECT statements and dive into the advanced programmability features of SQL. We cover how to handle complex conditionals with the CASE statement, the right way to manage NULL values to prevent math errors, and the absolute best practices for creating temporary table backups before running massive updates. Finally, we wrap up by packaging our logic into dynamic, secure Stored Procedures. What you will learn in this session: Best Practices & Operators: Writing readable code with comments and applying math/string operators. The CASE Statement: Implementing IF-THEN-ELSE logic directly inside your SQL queries. NULL Functions: Mastering ISNULL and COALESCE to prevent query failures when data is missing. Table Cloning: Using SELECT INTO for quick backups and INSERT INTO SELECT for archiving records. Stored Procedures: Writing dynamic, reusable SQL code that protects against injection attacks.