SQL INNER JOIN keyword usage tutorial
When the keyword of inner join is returned, at least one row in the competition is returned.
SQL Syntax of INNER JOIN
SELECT column_name(s)FROM table_name1INNER JOIN table_name2 ON table_name1.column_name=table_name2.column_name
PS:Inner join is the same as JOIN.
Let's take a look at an example.
P_Id |
LastName |
FirstName |
Address |
City |
1 |
Hansen |
Ola |
Timoteivn 10 |
Sandnes |
2 |
Svendson |
Tove |
Borgvn 23 |
Sandnes |
3 |
Pettersen |
Kari |
Storgt 20 |
Stavanger |
Let's take a look at the orders table.
_ Id |
OrderNo |
P_Id |
1 |
77895 |
3 |
2 |
44678 |
3 |
3 |
22456 |
1 |
4 |
24562 |
1 |
5 |
34764 |
15 |
Now, we want to list any commands of all people.
We use the following SELECT statement:
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNoFROM PersonsINNER JOIN OrdersON Persons.P_Id=Orders.P_IdORDER BY Persons.LastName
LastName |
FirstName |
OrderNo |
Hansen |
Ola |
22456 |
Hansen |
Ola |
24562 |
Pettersen |
Kari |
77895 |
Pettersen |
Kari |
44678 |
When the keyword of inner join orders is returned, at least one row in the competition is returned. If there are "orders" listed in "persons" that do not match ",
Will these rows be listed.