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Query

In databases, a query is a request to retrieve, insert, update or delete data. Written in SQL (Structured Query Language), queries can be simple, like fetching all rows from a table, or complex, involving joins, conditions and aggregations. They are essential for interacting with and managing database information efficiently.

Top Query Articles

Common Table Expressions (CTE) in SQL : A in-depth Guide
Learn what Common Table Expressions (CTE) are in SQL, how they work, syntax examples, benefits and when to use them for cleaner queries.
SQL Constraints Explained : Types, Syntax & Real-World Use Cases
SQL constraints are rules that enforce data integrity in tables. Learn what constraints are, types of SQL constraints, how to add them to columns and real-world use cases.
How to Drop a Table in SQL
DROP TABLE in SQL is a DDL command used to permanently remove a table along with its data, indexes, constraints, and metadata. Learn syntax, risks, and safe usage.
Temporary Table in SQL
Temporary tables in SQL store session-based data. Learn what temporary tables are, how to create them, use cases and automatic deletion behavior.
Cloning Table in SQL
Learn how to clone a table in SQL to copy structure, data or both. Ideal for backups, testing and creating reusable table templates efficiently.
How to Rename a Tables in SQL
Rename Table command in SQL | how to rename a table in a database | how to rename a table in SQL | rename tables in MYSQL, SQL Server and Oracle
How to Show Tables in SQL
SHOW Table command in SQL | how to show all tables in a database | list of all user define tables in SQL | show tables in MYSQL, SQL Server and Oracle | retrieve list of all database tables in relational database.
Foreign Key in SQL
SQL - Foreign Key - In SQL, a foreign key is a column (or a set of columns) in one table that uniquely identifies a row in another table. It establishes a relationship between the parent table (which contains the primary key) and the child table (which contains the foreign key).
UNIQUE Key in SQL: Constraint & Syntax Explained with FAQs
Learn what a UNIQUE key in SQL is and how it enforces distinct values in columns. Understand syntax, use cases and differences from primary keys.
How to Create Primary Key in SQL (With Syntax & FAQs)
Learn how to create a primary key in SQL using syntax and examples. Ensure unique records, improve query performance and build table relationships.

Popular Topics

System Design
System design is the process of defining the architecture, components, modules, interfaces and data flow of a system to meet specific requirements. It focuses on creating scalable, efficient and maintainable solutions, covering both high-level design (HLD) and low-level design (LLD). Essential for building reliable, high-performance software systems.
Database
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects. The data are typically organized to model aspects of reality in a way that supports processes requiring information. Use this tag if you have questions about designing a database.
DSA
DSA (Data Structures and Algorithms) is a fundamental concept in computer science that focuses on efficiently storing, organizing and processing data. Data structures like arrays, linked lists, stacks and trees manage data, while algorithms provide step-by-step solutions to problems. Mastering DSA is essential for writing optimized, scalable and high-performance code.
AI
Artificial Intelligence (AI) is the simulation of human intelligence in machines, enabling them to think, learn and make decisions. It powers systems to solve problems, recognize patterns, understand language and adapt over time. AI is used in various fields, including robotics, healthcare, finance and everyday applications like virtual assistants.
Array
An array is a linear data structure that stores multiple elements of the same type in contiguous memory locations. It allows fast access using index positions, making operations like retrieval efficient. Arrays are widely used for organizing data, implementing algorithms and building other data structures. However, their size is fixed, making resizing difficult compared to dynamic collections.
MySQL
MySQL is an open-source relational database management system widely used for storing and managing structured data. It supports SQL for querying, updating and controlling data efficiently. Known for reliability, speed and scalability, MySQL powers web applications, enterprise systems and cloud platforms. It is commonly used with PHP, Java, Python and modern application stacks like LAMP and MERN.
Application Design
Application design is the process of planning and structuring an application’s architecture, user interface, data flow and functionality to meet user and business requirements. It involves decisions on technology stack, design patterns, scalability and security. Good application design ensures performance, maintainability and a seamless user experience across platforms and devices.
Interview Preparation
Interview Preparation is the process of getting ready to perform confidently and effectively in a job interview. It includes researching the company, understanding the job role, practicing common interview questions, improving communication skills and reviewing technical or domain knowledge. Proper interview preparation increases confidence, reduces anxiety, and improves your chances of securing the job.
C#
C# (C-Sharp) is a modern, object-oriented programming language developed by Microsoft for building secure, scalable applications. It runs on the .NET platform and supports features like strong typing, garbage collection, LINQ, async programming and cross-platform development. C# is widely used for web, desktop, game development (Unity), cloud services and enterprise-level software solutions.
Java
Java is a high-level object-oriented programming language. it's firstly released by Sun Microsystems in 1995. Use this tag when you're having queries using or understanding the language. This tag is also applicable to Java libraries and frameworks.
Popular Articles
You are given two integer arrays arr1 and arr2, sorted in accending order, and two integers m and n, representing the number of elements in arr1 and arr2 respectively. Merge arr1 and arr2 into a single array sorted in accending order.
Mastering the Singleton Design Pattern in C#, Singleton Design Pattern in Depth: Structure, Use Cases and Best Practices, in depth design pattern, LLD , low level design
A Structured Approach to Cracking Technical Interviews. how to prepare for Technical Interviews? Technical Interviews preparation guideline
Amazon Transaction Logs (example question), Amazon Transaction Logs Interview question
How to Approach HR Interview Questions , What to Keep in Mind While Answering HR Interview Questions, HR Interview Questions and Answers
Learn how to create a primary key in SQL using syntax and examples. Ensure unique records, improve query performance and build table relationships.
Length of the Longest Substring Without Repeating Characters | Given a string str find the length of the longest substring without repeating characters | find the length of the longest substring without repeating characters in a given string |
Top High-Level Design(HLD) Interview Questions and answers, HLD QnA, HLD interview preparation
List Handling in Java vs C# vs C++ A Deep Comparison, This comparison provides a full view java , c# and c++ List like data structures

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