1. Data Query Language (DQL) Queries:

   • Purpose: These queries are used to retrieve data from the database.

   • Key SQL Statement: SELECT

   • Examples:

     • Retrieving records from a table.
     • Performing aggregate calculations (e.g., SUM, AVG, COUNT) on data.
     • Sorting and filtering data using conditions.

     Data Query Language (DQL) Queries

2. Data Definition Language (DDL) Queries:

   • Purpose: These queries are used to define, modify, or delete database structures and objects.

   • Key SQL Statements: CREATE, ALTER, DROP,TRUNCATE

   • Examples:

     • Creating tables, views, and indexes.
     • Modifying table structures (e.g., adding or deleting columns).
     • Dropping tables and other database objects.

     Data Definition Language (DDL) queries

3. Data Manipulation Language (DML) Queries:

   • Purpose: These queries are used to insert, update, and delete data in the database.

   • Key SQL Statements: INSERT, UPDATE, DELETE

   • Examples:

     • Inserting new records into a table.
     • Updating existing records with new values.
     • Deleting records from a table.

     Data Manipulation Language (DML) Queries

4. Data Control Language (DCL) Queries:

   • Purpose: These queries are used to control access to data and database objects by managing user privileges and permissions.
   • Key SQL Statements: GRANT, REVOKE
   • Examples:
     • Granting or revoking specific privileges to users or roles.
     • Managing access control for database objects.

   Data Control Language (DCL) Queries

These four types of queries cover the primary operations performed in a relational database system. DQL queries are used for data retrieval, DDL queries for defining and modifying database structures, DML queries for data manipulation, and DCL queries for controlling data access and permissions.