Basic SQL Queries

·        To CREATE DATABASE statement is used to create a new SQL database.

CREATE DATABASE databasename;

·        To Drop Database

DROP DATABASE databasename;

·        To Create Table

CREATE TABLE Persons (PersonID int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255));

·        

     To Drop table

DROP TABLE table_name;

·      

         To Alter table

ALTER TABLE table_name ADD column_name datatype;

·        To Add Constrains

ALTER TABLE Persons ADD CONSTRAINT PK_Person PRIMARY KEY (ID,LastName);

·        To Drop Constrains

ALTER TABLE Persons DROP CONSTRAINT PK_Person;

·        To Insert values

INSERT INTO Customers (CustomerName, ContactName, Address, City, PostalCode, Country) VALUES ('Cardinal', 'Tom B. Erichsen', 'Skagen 21', 'Stavanger', '4006', 'Norway');

·        To Select Values from table

SELECT CustomerName, City FROM Customers;

SELECT * FROM Customers WHERE Country='Mexico';

SELECT * FROM Customers WHERE Country='Germany' AND City='Berlin';

SELECT * FROM Customers WHERE City='Berlin' OR City='München';

SELECT * FROM Customers WHERE NOT Country='Germany';

SELECT * FROM Customers ORDER BY Country;

SELECT LastName, FirstName, Address FROM Persons WHERE Address IS NULL;

·        To Update row of a table

UPDATE Customers SET ContactName = 'Alfred Schmidt', City= 'Frankfurt'
WHERE CustomerID = 1;

·        To Delete Row of a table

DELETE FROM Customers WHERE CustomerName='Alfreds Futterkiste';