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.
What is Hive? Important Points, Interview Questions
Hive a Data warehouse infra Hive is an open-source data warehouse infrastructure built on top of Hadoop for providing data summarization, query, and analysis. It allows users to query and manage large datasets residing in distributed storage using a SQL-like language called HiveQL. Here’s an overview of Hive: Features of Hive: Components of Hive: Use…
How SQL queries execute in a database, using a real query example.
Understanding how an SQL query executes in a database is essential for performance tuning and system design. Here’s a step-by-step breakdown of what happens under the hood when you run an SQL query like: 🧭 0. Query Input (Your SQL) You submit the SQL query via: ⚙️ Step-by-Step SQL Query Execution 🧩 Step 1: Parsing…
Comprehensive guide to important Points and tricky conceptual issues in SQL
Here’s a comprehensive guide to important and tricky conceptual issues in SQL, including NULL behavior, joins, filters, grouping, ordering, and subqueries. ✅ 1. NULLs: The #1 source of confusion a. NULL ≠ NULL b. NOT IN with NULL c. Arithmetic with NULL ✅ 2. JOIN Issues a. INNER JOIN drops unmatched rows. b. LEFT JOIN…
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…
Spark SQL Join Types- Syntax examples, Comparision
Spark SQL supports several types of joins, each suited to different use cases. Below is a detailed explanation of each join type, including syntax examples and comparisons. Types of Joins in Spark SQL 1. Inner Join An inner join returns only the rows that have matching values in both tables. Syntax: Example: 2. Left (Outer)…
Date and Time Functions- Pyspark Dataframes & Pyspark Sql Queries
A quick reference for date manipulation in PySpark:– Function Description Works On Example (Spark SQL) Example (DataFrame API) to_date Converts string to date. String TO_DATE(‘2024-01-15’, ‘yyyy-MM-dd’) to_date(col(“date_str”), “yyyy-MM-dd”) to_timestamp Converts string to timestamp. String TO_TIMESTAMP(‘2024-01-15 12:34:56’, ‘yyyy-MM-dd HH:mm:ss’) to_timestamp(col(“timestamp_str”), “yyyy-MM-dd HH:mm:ss”) date_format Formats date or timestamp as a string. Date, Timestamp DATE_FORMAT(CURRENT_DATE, ‘dd-MM-yyyy’) date_format(col(“date_col”), “dd-MM-yyyy”)…
Apache Spark RDDs: Comprehensive Tutorial
Apache Spark RDDs: Comprehensive Tutorial Table of Contents Introduction to RDDs Resilient Distributed Datasets (RDDs) are the fundamental data structure of Spark. They are: Key Characteristics: RDD Lineage RDD lineage is a graph of all the parent RDDs of an RDD. It’s built as a result of applying transformations to the RDD. Output would show…
Complete crisp PySpark Interview Q&A Cheat Sheet
Certainly! Here’s the complete crisp PySpark Interview Q&A Cheat Sheet with all your questions so far, formatted consistently for flashcards, Excel, or cheat sheet use: Question Answer How do you handle schema mismatch when reading multiple JSON/Parquet files with different structures? Use .option(“mergeSchema”, “true”) when reading Parquet files; for JSON, unify schemas by selecting common…
Python Lists- how it is created, stored in memory, and how inbuilt methods work — including internal implementation details
In Python, a list is a mutable, ordered collection of items. Let’s break down how it is created, stored in memory, and how inbuilt methods work — including internal implementation details. 🔹 1. Creating a List 🔹 2. How Python List is Stored in Memory Python lists are implemented as dynamic arrays (not linked lists…
Data Engineer Interview Questions Set1
Explain a scenario on schema evolution in data pipelines Here’s an automated Python script using PySpark that performs schema evolution between two datasets (e.g., two Parquet files or DataFrames): ✅ Features: 🔧 Prerequisites: 🧠 Script: Schema Evolution Handler 🔍 Output: 💡 Notes: Automated script for schema evolution. first to check what fields are missing or…