SQL commands are the instructions used to communicate with a database. They are used to perform tasks such as creating databases, adding and modifying data, and querying data. SQL commands can be divided into three categories: Data Manipulation Language (DML), Data Definition Language (DDL), and Data Control Language (DCL). DML commands are used to manipulate data, DDL commands are used to define the structure of a database, and DCL commands are used to control access to a database.SQL is a standard computer language for relational database management and data manipulation. SQL commands are used to perform tasks such as updating data in a database, or retrieving data from a database. Some common SQL commands include: SELECT, INSERT, UPDATE, DELETE, CREATE, and DROP SQL is a standard database query language that is used to manipulate and query data stored in relational databases. SQL commands are divided into four categories: Data Manipulation Language (DML), Data Definition Language (DDL), Data Control Language (DCL), and Transaction Control Statements (TCS). DML statements are used to retrieve, insert, update, and delete data from a database. DDL statements are used to create and modify database objects such as tables, views, procedures, and functions. DCL statements are used to control access to database objects. TCS statements are used to manage transactions in a database.