What is SQL?
SQL (pronounced “ess-que-el”) stands for Structured Query Language. SQL is used to communicate with a database. SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987. SQL lets you access and manipulates databases. Some common relational database management systems that use SQL are Oracle, Sybase, Microsoft SQL Server, Access, Ingres, etc.
What Can SQL do?
Most common usage of SQL involves-
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert records in a database
- SQL can update records in a database
- SQL can delete records from a database
- SQL can create new databases and tables in the database
Why we need it?
- SQL is used everywhere.
- It’s in high demand because so many companies use it.
- It is easy to use and gives quick access to information.
- It is a gateway to other programming.
- Although there are alternatives, SQL is not going anywhere.
Some of The Most Important SQL Commands are-
SELECT – extracts data from a database
UPDATE – updates data in a database
DELETE – deletes data from a database
INSERT INTO – inserts new data into a database
CREATE DATABASE – creates a new database
ALTER DATABASE – modifies a database
CREATE TABLE – creates a new table
ALTER TABLE – modifies a table
DROP TABLE – deletes a table
CREATE INDEX – creates an index (search key)
DROP INDEX – deletes an index
Use this link for a list of all SQL commands.
This link is a good video lesson to learn SQL.
And for practising SQL this link is excellent.