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Introduction to SQL
Importance and Applications
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SQL SELECT
SQL Select Distinct
SQL Select Distinct
SQL Where
SQL ORDER BY Keyword
SQL Airthmetic Operators
SQL Comparison Operator
SQL Logical Operator
SQL Bitwise Operator
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SQL LIKE Operator
SQL ALL Operator
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Introduction to SQL

History of SQL

  • SQL was developed by Raymond Boycee in 1970 by IBM company but the current owner of SQL is Oracle.
  • Raymond Boycee is known as the father of SQL
  • In earlier days SQL was known as ‘SEQUEL’ means (simple English query executable language)
  • ANSI Standards (American National Standard Institute) acquired SEQUEL and then renamed it SQL in the year 1979

Key Points:

  • SQL stands for Structured Query Language.
  • It is used to interact with the database.
  • It is a database language for storing, manipulating and retrieving data in a relational database management system(RDBMS).

Basic SQL Commands:

  • SELECT: It is used to retrieve data from one or more tables.
  • INSERT: It is used to add new rows of data into a table.
  • UPDATE: It is used to modify existing data in a table.
  • DELETE: It is used to remove data from a table.

Basic Terminologies

  • Database: It is a Centralized place that is used to store some data and manage the data.
  • Schema: The collection of tables in the database is known as Schema.
  • Entity: An entity is a real-world object each and every entity has its own attributes and properties which are described about them.
  • Data: Data is a row or Record that describes all the column names or attributes of a table or entity.
  • DBMS: It is software that is used to store some data and manage the data. Generally, DBMS is a combination of database and management system
    :- Management services provided by DBMS are:
    1. Inserting
    2. Deleting
    3. Updating
    4. Accessing
  • Record: The record is nothing but a row. The horizontal part of a table contains a serial set of columns.
  • Field: The field is nothing but a column. The vertical part of a table of one datatype
  • SQL Queries: Queries are statements written in SQL to perform certain operations like inserting, retrieving, deleting, and updating specific data from the database. 
  • Database Schema: The structure of the database is defined by its schema, which includes tables, columns, data types, relationships, and constraints the schema outlines how the data is organized.
  • Constraints: Constraints enforce rules on the data stored in the database, ensuring data integrity
  • Normalization: This database design technique aims to minimize data redundancy and improve data integrity by organizing tables in a specific way.