Tag: SQL

Table of Contents Introduction Why Error Handling Matters in SQL Types of Errors in SQL Syntax Errors vs Runtime Errors Understanding Transaction Errors Rollbacks for Safe Error Recovery Error Handling in...

Table of Contents Introduction What Are Stored Procedures and Functions? Benefits of Using Stored Routines Stored Procedures vs Functions: Key Differences Syntax for Creating Stored Procedures Executing a Stored Procedure Parameters...

Table of Contents Introduction What Is a Trigger in SQL? Why Use Triggers? Types of Triggers Syntax of a Trigger BEFORE vs AFTER Triggers INSERT, UPDATE, and DELETE Triggers Trigger Events: Row-Level...

Table of Contents Introduction What Are Constraints in SQL? Why Use Constraints? NOT NULL Constraint UNIQUE Constraint CHECK Constraint DEFAULT Constraint Combining Multiple Constraints Adding Constraints to Existing Tables Dropping Constraints Naming Constraints for Clarity Column-Level...

Table of Contents Introduction What Is a Transaction in SQL? Why Transactions Matter The ACID Properties Transaction Control Commands BEGIN or START TRANSACTION COMMIT – Finalizing Changes ROLLBACK – Undoing Changes Autocommit Behavior Nested...

Table of Contents Introduction Why Performance Tuning Matters What Is Query Optimization? What Is an Index in SQL? Types of Indexes How Indexes Work Internally Benefits of Using Indexes When Not to...

Table of Contents Introduction What Are LEAD() and LAG() Functions? Why Use These Functions? Syntax of LEAD() and LAG() Basic LAG() Example Basic LEAD() Example Comparing Current and Previous/Next Rows Using PARTITION...

Table of Contents Introduction What Are Window Functions? Why Use Window Functions? Basic Syntax of a Window Function Introduction to ROW_NUMBER() Example: Using ROW_NUMBER() Introduction to RANK() Example: Using RANK() Introduction to DENSE_RANK() Example:...

Table of Contents Introduction What is a Common Table Expression (CTE)? Why Use CTEs? Syntax of a CTE CTE vs Subquery vs View Multiple CTEs in a Query Using CTEs with...

Table of Contents Introduction What is a View in SQL? Benefits of Using Views Syntax for Creating a View Querying Data from a View Updating a View Rules and Limitations of...

Table of Contents Introduction What is the DISTINCT Keyword? Why and When to Use DISTINCT Syntax of DISTINCT How DISTINCT Works Internally DISTINCT on a Single Column DISTINCT on Multiple Columns DISTINCT...

Table of Contents Introduction Why Mathematical Functions Matter in SQL Overview of Common SQL Math Functions ROUND() – Round Numbers CEIL() or CEILING() – Round Up FLOOR() – Round Down MOD()...