inner join sql definition code example

Example 1: inner join

INNER JOIN is used when retrieving data from
multiple tables and will return only matching data.

example=
Select P.FIRST_NAME , M.DRUG_ID
FROM PATIENTS P
INNER JOIN MEDICATIONS M ON P.PATIENTS_ID = M.PATIENTS_ID

Example 2: left join sql

#LEFT JOIN: Return all rows from the left table, even if there are no matches in the right
#table 
syntax->SELECT column_name(s)
FROM table_name1
LEFT JOIN table_name2
ON table_name1.column_name=table_name2.column_name 
////example/////
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons
LEFT JOIN Orders
ON Persons.P_Id=Orders.P_Id
ORDER BY Persons.LastName