Introduction to SQL

SQL is a standard language for sorting, manipulating and retrieving data from databases. SQL stands for Structured Query Language that let you access and manipulate databases.

Power of SQL:

  • SQL can execute queries against a database
  • SQL is used to insert data into a database
  • SQL is used to retrieve data from a database
  • SQL is used to update/edit data of a database
  • SQL is used to delete/remove data of a database
  • SQL is used to create database and tables
  • SQL is used to create stored procedures
  • SQL is used to create view in a database
  • SQL is used to set permission on tables, procedures and views

Commands of SQL

Below are some most important and basic commands of SQL.

Command Description
SELECT It extracts data from a database
UPDATE It updates data in a database
DELETE It deletes data from a database
INSERT INTO It inserts new data into a database
CREATE DATABASE It creates a new database
ALTER DATABASE It modifies a database
CREATE TABLE It creates a new table
ALTER TABLE It modifies a table
DROP TABLE It deletes a table
CREATE INDEX It creates an index
DROP INDEX It deletes an index

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