SQL Inner Join
As discussed in the previous lesson, you should use the SQL INNER JOIN when you only want to return records where there is at least one row in both tables that match the join condition.
Example SQL statement
SELECT * FROM Individual
INNER JOIN Publisher
ON Individual.IndividualId = Publisher.IndividualId
WHERE Individual.IndividualId = '2'
Source Tables
Left Table
| Id | FirstName | LastName | UserName |
|---|---|---|---|
| 1 | Fred | Flinstone | freddo |
| 2 | Homer | Simpson | homey |
| 3 | Homer | Brown | notsofamous |
| 4 | Ozzy | Ozzbourne | sabbath |
| 5 | Homer | Gain | noplacelike |
Right Table
| IndividualId | AccessLevel |
|---|---|
| 1 | Administrator |
| 2 | Contributor |
| 3 | Contributor |
| 4 | Contributor |
| 10 | Administrator |
Result
| IndividualId | FirstName | LastName | UserName | IndividualId | AccessLevel |
|---|---|---|---|---|---|
| 2 | Homer | Simpson | homey | 2 | Contributor |
Next lesson covers the SQL OUTER JOIN.