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Category: Tutorials
Q1.–We are working with large datasets in PySpark, such as joining a 30GB table with a 1TB table or Various Transformation on 30 GB Data, we have 100 cores limit to use per user , what can be best configuration and Optimization strategy to use in pyspark ? will 100 cores are enough or should…
Data cleaning in SQL is a crucial step in data preprocessing, especially when working with real-world messy datasets. Below is a structured breakdown of SQL data cleaning steps, methods, functions, and complex use cases you can apply in real projects or interviews. ✅ Common SQL Data Cleaning Steps & Methods Step Method / Function Example…
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…
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…
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…
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…
Here’s a complete Azure Databricks tutorial roadmap (Beginner → Advanced), tailored for Data Engineering interviews in India, including key concepts, technical terms, use cases, and interview Q&A: ✅ What is Azure Databricks? Azure Databricks is a fast, easy, and collaborative Apache Spark-based analytics platform optimized for the Microsoft Azure cloud. 🔗 How Azure Databricks integrates…
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)…
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”)…
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 the transformation steps: Creating RDDs…