What is SQL (Structured Query Language)

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SQL (Structured Query Language) is a standardized programming language used to manage and manipulate relational databases. It allows users to perform various operations on the data stored in a database. Here’s a brief overview:

Key Features:

  • Data Querying: SQL allows users to query the database to retrieve specific data using the SELECT statement.
  • Data Manipulation: Users can insert, update, and delete data in the database using INSERT, UPDATE, and DELETE statements, respectively.
  • Schema Creation and Modification: SQL provides commands to create and modify the structure of database objects (tables, indexes, views) using CREATE, ALTER, and DROP statements.
  • Data Control: SQL includes commands to control access to data and database objects, such as GRANT and REVOKE.
  • Transaction Control: It supports transactions, which are sequences of operations executed as a single unit, ensuring data integrity. Commands like BEGIN TRANSACTION, COMMIT, and ROLLBACK are used for this purpose.

Basic SQL Commands:

  1. SELECT: Retrieves data from one or more tables.
    SELECT column1, column2 FROM table_name WHERE condition;
  2. INSERT: Adds new rows to a table.
    INSERT INTO table_name (column1, column2) VALUES (value1, value2);
  3. UPDATE: Modifies existing data in a table.
    UPDATE table_name SET column1 = value1 WHERE condition;
  4. DELETE: Removes rows from a table.
    DELETE FROM table_name WHERE condition;
  5. CREATE TABLE: Creates a new table.
    CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    ...
    );
  6. ALTER TABLE: Modifies an existing table.
    ALTER TABLE table_name ADD column_name datatype;
  7. DROP TABLE: Deletes a table.
    DROP TABLE table_name;

SQL Variants:

Different relational database management systems (RDBMS) like MySQL, PostgreSQL, Microsoft SQL Server, and Oracle Database use SQL with some variations and additional proprietary extensions.

SQL is widely used in database management due to its simplicity, powerful querying capabilities, and standardized nature, making it a fundamental skill for database administrators, developers, and data analysts.

For more information and tutorials on SQL click HERE

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