Welcome to the Future – AI Hints Today
Keyword is AI– This is your go-to space to ask questions, share programming tips, and engage with fellow coding enthusiasts. Whether you’re a beginner or an expert, our community is here to support your journey in coding. Dive into discussions on various programming languages, solve challenges, and exchange knowledge to enhance your skills.
SQL Tricky Conceptual Interview Questions
Great question! In SQL, DELETE, TRUNCATE, and DROP are used to remove data—but they work very differently in terms of what they remove, speed, rollback, and usage. Here’s a quick comparison followed by detailed explanations with examples: 🔍 Quick Comparison FeatureDELETETRUNCATEDROPWhat it removesRowsAll rowsEntire table (structure + data)Can use WHERE✅ Yes❌ No❌ NoRollback (Transactional)✅ Yes…
Data Engineer Interview Questions Set4
Perfect! Here’s everything inline, right in this window: ✅ Part 1: Spark Cluster Simulation Notebook (Inline Code) This Jupyter/Databricks notebook simulates how Spark behaves across cluster components: 🧠 Use .explain(True) at any step to inspect execution plan. ✅ Part 2: Spark Execution Flow — Mindmap Style Summary (Inline) ✅ Optional: Mindmap Format You Can Copy…
Data Engineer Interview Questions Set3
Let’s visualize how Spark schedules tasks when reading files (like CSV, Parquet, or from Hive), based on: ⚙️ Step-by-Step: How Spark Schedules Tasks from Files 🔹 Step 1: Spark reads file metadata When you call: 🔹 Step 2: Input Splits → Tasks File Size Block Size Input Splits Resulting Tasks 1 file, 1 GB 128…
Data Engineer Interview Questions Set2
Great question! Understanding the difference between a UDF (User Defined Function) and built-in Spark SQL functions is crucial for writing performant PySpark code. 🔍 UDF vs In-built Spark Function Feature UDF (User Defined Function) In-built Spark Function Definition A custom function defined by the user to extend Spark’s capabilities Predefined, optimized functions provided by Spark…
What is Hive? Important Points, Interview Questions
Yes, you’re absolutely right to explore this distinction. ✅ Hive does support ACID properties, starting from Hive 0.14+ (full features in Hive 3.x). ❌ Vanilla Apache Spark (especially before Delta Lake or Hudi/Iceberg) does NOT support ACID natively. Let’s break this down clearly: ✅ Hive with ACID – YES Apache Hive supports ACID transactions for…
How SQL queries execute in a database, using a real query example.
We should combine both perspectives—the logical flow (SQL-level) and the system-level architecture (engine internals)—into a comprehensive, step-by-step guide on how SQL queries execute in a database, using a real query example. 🧠 How a SQL Query Executes (Combined Explanation) ✅ Example Query: This query goes through the following four high-level stages, each containing deeper substeps.…
Comprehensive guide to important Points and tricky conceptual issues in SQL
Let me explain why NOT IN can give incorrect results in SQL/Spark SQL when NULL is involved, and why LEFT ANTI JOIN is preferred in such cases—with an example. 🔥 Problem: NOT IN + NULL = Unexpected behavior In SQL, when you write: This behaves differently if any value in last_week.user_id is NULL. ❌ What…
RDD and Dataframes in PySpark- Code Snipppets
Where to Use Python Traditional Coding in PySpark Scripts Using traditional Python coding in a PySpark script is common and beneficial for handling tasks that are not inherently distributed or do not involve large-scale data processing. Integrating Python with a PySpark script in a modular way ensures that different responsibilities are clearly separated and the…
Azure Databricks tutorial roadmap (Beginner → Advanced), tailored for Data Engineering interviews in India
Here’s your complete tutorial on Apache Spark DataFrame in Azure Databricks, covering everything from basics to advanced operations exclusive to Azure Databricks (not available in standard on-prem PySpark setups). 📘 Azure Databricks DataFrame Tutorial (2025) 📌 Part 1: What is a DataFrame in Spark? A DataFrame is a distributed, table-like, high-level API for structured and…
Spark SQL Join Types- Syntax examples, Comparision
Here are Spark SQL join questions that are complex, interview-oriented, and hands-on — each with sample data and expected output to test real-world logic. ✅ Setup: Sample DataFrames 🔹 Employee Table (emp) 🔹 Department Table (dept) 🧠 1. Find all employees, including those without a department. Show department name as Unknown if not available. 🧩…