book reference

https://www.amazon.in/Database-Systems-Concepts-Sixth-Silberschatz/dp/0071325220

.................

JOINS

1) LEFT JOIN

USE test //DB

CREATE TABLE RS (

ID int

);

CREATE TABLE LS (

ID int

);

INSERT INTO LS (ID)

VALUES (2);

INSERT INTO RS (ID)

VALUES (1);

SELECT * FROM LS ;

SELECT * FROM RS ;

SELECT * FROM LS

SELECT * FROM RS

SELECT *

from LS

LEFT JOIN RS

ON LS.ID = RS.ID

SELECT Customers.CustomerName, Orders.OrderID

FROM Customers

LEFT JOIN Orders ON Customers.CustomerID = Orders.CustomerID

.................................................

USE test

CREATE TABLE RS (

ID int ,

COL2 VARCHAR(12)

);

CREATE TABLE LS (

ID int ,

COL4 VARCHAR(12)

);

INSERT INTO LS (ID ,COL4)

VALUES (1 ,'AAA');

INSERT INTO RS (ID ,COL2)

VALUES (2 ,'DDD');

SELECT * FROM LS ;

SELECT * FROM RS ;

SELECT *

from LS

LEFT JOIN RS

ON LS.ID = RS.ID