SQL Codes- Intro

**What is SQL? **SQL stands for Structured Query Language **SQL lets you access and manipulate databases **SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987

*** To select all the columns from the table '*' is used to select from a table named 'Customer'

SELECT * FROM Customers;

**SELECT column1, column2, ... **FROM table_name;

***SQL keywords in upper-case.

**Semicolon after SQL Statements? **Some database systems require a semicolon at the end of each SQL statement. **Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server. **We will use semicolon at the end of each SQL statement.

**Some of The Most Important SQL Commands **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