SQL-SQL Learning and Practice

Introduction to SQL

SQL, or Structured Query Language, is a standard programming language specifically designed for managing and manipulating relational databases. It enables users to execute a wide range of operations, including querying data, updating records, and managing database structures. SQL was developed to work with relational databases, which organize data into tables consisting of rows and columns. Each table represents a different entity (e.g., customers, orders) and can be linked to others through relational keys, allowing for complex queries across multiple tables. Examples of SQL's functionality include retrieving data from a database through SELECT statements, updating records using UPDATE statements, inserting new data with INSERT INTO commands, and deleting records with DELETE statements. For instance, to query a list of customer names from a customer table, one might use: `SELECT name FROM customers;`. This basic yet powerful operation exemplifies SQL's design purpose: to provide a straightforward, readable syntax for complex data manipulation and retrieval operations. Powered by ChatGPT-4o。