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.

CommandDescription
SELECTIt extracts data from a database
UPDATEIt updates data in a database
DELETEIt deletes data from a database
INSERT INTOIt inserts new data into a database
CREATE DATABASEIt creates a new database
ALTER DATABASEIt modifies a database
CREATE TABLEIt creates a new table
ALTER TABLEIt modifies a table
DROP TABLEIt deletes a table
CREATE INDEXIt creates an index
DROP INDEXIt deletes an index