Unique constraint in SQL

In this blog I will explain Unique constraint in SQL.If i create a UNIQUE constraint, i can't insert duplicate data in that column.
The UNIQUE constraint ensures that all values in a column are distinct.
Example i have created a Table:-

CREATE TABLE UNIQUE_EXAMPLE
(
    ID INT UNIQUE,
    Name VARCHAR(50)
)

INSERT INTO UNIQUE_EXAMPLE values ('1','Mohit');
INSERT INTO UNIQUE_EXAMPLE values ('2','Rahul');
INSERT INTO UNIQUE_EXAMPLE values ('3','Deepak');

INSERT INTO Customer UNIQUE_EXAMPLE('3','Monu');