SQL

Visualizing SQL Query Performance with EXPLAIN Plans   Performance tuning is a critical aspect of working with relational databases. In PostgreSQL, understanding how a query gets executed is the first…

Speed Up SQL Queries Using Indexes—With Before-and-After Benchmarks   SQL performance tuning is one of the most impactful ways to improve an application’s responsiveness. One of the most powerful tools…

SQL Query Recipes for Cleaning Dirty Data   Dirty data is a persistent challenge in every data system. Whether it's duplicate records, null values, inconsistent formatting, or typos, bad data…

SQL Window Functions: Ranking Sales by Region in One Query   Window functions in SQL offer a powerful way to perform calculations across sets of rows related to the current…

SQL Window Functions for Time-Based Event Tracking   Tracking user behavior or system events over time is a core requirement in analytics, monitoring, and debugging. Fortunately, SQL window functions are…

Efficient SQL: Deduplicate Rows Without Losing Data   Duplicates in your database can lead to bloated storage, inaccurate analytics, and unexpected behavior. But purging them blindly can mean losing valuable…

'SELECT *' is Lazy—Write Safer Dynamic Queries in SQL Using Parameters   One of the most common mistakes developers make when working with SQL is using SELECT * indiscriminately and…

SQL Window Functions Demystified with Real Sales Data   SQL window functions are an underrated powerhouse for data manipulation, especially in analytics and reporting. When working with e-commerce data —…

'GROUP BY' Pitfalls: Avoiding Common SQL Aggregation Errors   Introduction SQL's GROUP BY clause is a powerful tool for summarizing data, but it's also a frequent source of confusion, especially…

Join Data From Multiple Tables With Ease: Advanced SQL Joins Explained   Working with relational databases often means working with multiple related tables. Whether you're building reports for an e-commerce…