SQL INNER JOIN Keyword
SQL INNER JOIN Keyword
The
INNER JOIN keyword return rows when there is at least one match in both tables.
SQL INNER JOIN Syntax
SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name=table_name2.column_name
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PS: INNER JOIN is the same as JOIN.
SQL INNER JOIN Example
The "Persons" table:
| P_Id |
LastName |
FirstName |
Address |
City |
| 1 |
Hansen |
Ola |
Timoteivn 10 |
Sandnes |
| 2 |
Svendson |
Tove |
Borgvn 23 |
Sandnes |
| 3 |
Pettersen |
Kari |
Storgt 20 |
Stavanger |
The "Orders" table:
| O_Id |
OrderNo |
P_Id |
| 1 |
77895 |
3 |
| 2 |
44678 |
3 |
| 3 |
22456 |
1 |
| 4 |
24562 |
1 |
| 5 |
34764 |
15 |
Now we want to list all the persons with any orders.
We use
the following SELECT
statement:
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons
INNER JOIN Orders
ON Persons.P_Id=Orders.P_Id
ORDER BY Persons.LastName |
The result-set will look like this:
| LastName |
FirstName |
OrderNo |
| Hansen |
Ola |
22456 |
| Hansen |
Ola |
24562 |
| Pettersen |
Kari |
77895 |
| Pettersen |
Kari |
44678 |
The INNER JOIN keyword return rows when there is at least one match in both
tables. If there are rows in
"Persons" that do not have matches in "Orders", those rows will
NOT be
listed.
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