What is SQL?

Structured Query Language (SQL) is a standardized programming language specifically designed for managing and manipulating relational databases. Its primary uses revolve around interacting with data stored in a structured, tabular format.

Key uses of SQL include:

• Data Definition (DDL): SQL is used to define the structure of a database. This includes creating, modifying, and deleting database objects such as tables, indexes, and views.

Code

    CREATE TABLE Customers (
        CustomerID INT PRIMARY KEY,
        FirstName VARCHAR(50),
        LastName VARCHAR(50)
    );

• Data Manipulation (DML): SQL enables the manipulation of data within the database. This involves inserting new data, updating existing data, and deleting data.

Code

    INSERT INTO Customers (CustomerID, FirstName, LastName)
    VALUES (1, 'John', 'Doe');

    UPDATE Customers
    SET FirstName = 'Jane'
    WHERE CustomerID = 1;

    DELETE FROM Customers
    WHERE CustomerID = 1;

• Data Querying (DQL): SQL is most commonly used for retrieving data from the database based on specific criteria. This allows users to extract relevant information for analysis or display.

Code

    SELECT FirstName, LastName
    FROM Customers
    WHERE LastName = 'Doe';