by Team AHT | Jan 4, 2025 | SQL
What is Indexing? Indexing is a data structure technique that allows the database to quickly locate and access specific data. It’s similar to the index at the back of a book, which helps you find specific pages quickly. How Indexing Works Index Creation: The...
by Team AHT | Dec 28, 2024 | SQL
Spark SQL Operators Cheatsheet 1. Arithmetic Operators OperatorSyntaxDescriptionExample+a + bAdds two valuesSELECT 5 + 3;-a – bSubtracts one value from anotherSELECT 5 – 3;*a * bMultiplies two valuesSELECT 5 * 3;/a / bDivides one value by anotherSELECT 6 /...
by Team AHT | Nov 25, 2024 | SQL
For Better understanding on Spark SQL windows Function and Best Usecases do refer our post Window functions in Oracle Pl/Sql and Hive explained and compared with examples. Window functions in Spark SQL are powerful tools that allow you to perform calculations across a...
by Team AHT | Nov 7, 2024 | SQL
Here’s an enhanced Spark SQL cheatsheet with additional details, covering join types, union types, and set operations like EXCEPT and INTERSECT, along with options for table management (DDL operations like UPDATE, INSERT, DELETE, etc.). This comprehensive sheet...
by Team AHT | Nov 7, 2024 | SQL
Here’s a categorized Spark SQL function reference, which organizes common Spark SQL functions by functionality. This can help with selecting the right function based on the operation you want to perform. 1. Aggregate Functions FunctionDescriptionExampleavg()Calculates...
by Team AHT | Nov 6, 2024 | SQL
CRUD stands for Create, Read, Update, and Delete. It’s a set of basic operations that are essential for managing data in a database or any persistent storage system. It refers to the four basic functions that any persistent storage application needs to perform....
by Team AHT | Nov 1, 2024 | SQL
Data Definition Language (DDL) – to define and modify the structure of a database. Data Manipulation Language (DML) – to access, manipulate, and modify data in a database. Data Control Language (DCL) – to control user access to the data in the database...
by Team AHT | Oct 2, 2024 | SQL
Partitioning in SQL, HiveQL, and Spark SQL is a technique used to divide large tables into smaller, more manageable pieces or partitions. These partitions are based on a column (or multiple columns) and help improve query performance, especially when dealing with...
by Team AHT | Oct 2, 2024 | SAS, SQL
PIVOT Clause in Spark sql or Mysql or Oracle Pl sql or Hive QL The PIVOT clause is a powerful tool in SQL that allows you to rotate rows into columns, making it easier to analyze and report data. Here’s how to use the PIVOT clause in Spark SQL, MySQL, Oracle...
by Team AHT | Sep 6, 2024 | SQL
SQL query flows through the Oracle engine in the following steps: Step 1: Parsing The SQL query is parsed to check syntax and semantics. The parser breaks the query into smaller components, such as keywords, identifiers, and literals. Step 2: Optimization The parsed...
by Team AHT | Aug 2, 2024 | SQL
Let’s list all possible places where subqueries in MySQL or Hive QL or Pyspark SQL Query can be used: 1. In the SELECT Clause Subqueries can compute a value for each row. SELECT employee_id, (SELECT COUNT(*) FROM project_assignments pa WHERE pa.employee_id =...
by Team AHT | Jun 26, 2024 | SQL
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 Inner Join Left (Outer) Join Right (Outer) Join Full (Outer) Join...
by Team AHT | Jun 26, 2024 | SQL
Temporary functions allow users to define functions that are session-specific and used to encapsulate reusable logic within a database session. While both PL/SQL and Spark SQL support the concept of user-defined functions, their implementation and usage differ...
by Team AHT | Jun 6, 2024 | SQL
Window functions, also known as analytic functions, perform calculations across a set of table rows that are somehow related to the current row. This is different from regular aggregate functions, which aggregate results for the entire set of rows. Both Oracle PL/SQL...
by Team AHT | Jun 6, 2024 | SQL
Common Table Expressions (CTEs) are a useful feature in SQL for simplifying complex queries and improving readability. Both Oracle PL/SQL and Apache Hive support CTEs, although there may be slight differences in their syntax and usage. Common Table Expressions in...
by Team AHT | Jun 5, 2024 | SQL
Function NameDescriptionExample UsageResultCONCATConcatenates two strings.SELECT CONCAT(‘Oracle’, ‘PL/SQL’) FROM dual;OraclePL/SQL“ (Concatenation)Concatenates two strings.LENGTHReturns the length of a string.SELECT...
by Team AHT | Jun 2, 2024 | SQL
Date and Time manipulation in Oracle SQL In Oracle SQL, date and time manipulation is essential for many database operations, ranging from basic date arithmetic to complex formatting and extraction. Here’s a guide covering various common operations you might...
by Team AHT | Apr 15, 2024 | SQL
What is database structure? A database structure is the blueprint that defines how data is arranged ,organized, stored, accessed, and managed within a database. It’s the underlying framework that ensures efficient data handling, minimizes redundancy, and...
by Team AHT | Apr 15, 2024 | SQL
SQL (Structured Query Language) supports various data types to represent different kinds of data. These data types define the format and constraints of the data stored in each column of a table. Here are some common SQL data types: Numeric Types: INT: Integer type,...
by Team AHT | Apr 15, 2024 | SQL
In this BlogPost we would like to define Most Basic Terms in SQL:- What is SQL, Data Database, DBMS , RDBMS. What is SQL? SQL is a language used for relational databases to query or get data out of a database. SQL is also referred to as SQL and is short for its...
by Team AHT | Apr 8, 2024 | SQL
Indexing in SQL is a technique used to improve the performance of queries by creating special data structures (indexes) that allow for faster data retrieval. Indexes are created on one or more columns of a table, and they store the values of those columns in a sorted...
by Team AHT | Apr 7, 2024 | SQL
LIKE Operator: The LIKE operator is used to search for a specified pattern in a column. It allows the use of wildcards: % (percent sign): Matches zero or more characters. _ (underscore): Matches any single character. Examples: SELECT * FROM employees WHERE last_name...
by Team AHT | Apr 7, 2024 | SQL
Normalization and denormalization are two opposing database design techniques aimed at achieving different goals. Let’s explore each concept: Normalization: Normalization is the process of organizing the data in a database to minimize redundancy and dependency....
by Team AHT | Apr 7, 2024 | SQL
Designing a well-structured and efficient database schema in SQL involves several steps and considerations. Here’s a comprehensive guide to help you design a database schema that meets your application requirements while ensuring efficiency, scalability, and...
by Team AHT | Apr 7, 2024 | SQL
Optimizing SQL performance is crucial for ensuring that database operations are efficient and scalable. Here are some steps you can take to optimize SQL performance: Indexing: Proper indexing can significantly improve query performance. Identify columns frequently...