SQL INNER JOIN Keyword
Submitted by admin on Tuesday, March 22, 2011 - 09:07.
SQL INNER JOIN is almost the same as the normal join. But the INNER JOIN will only list those rows which have at least one matching value from both tables.
SQL INNER JOIN Syntax
SELECT column_name(s) FROM First_table_name INNER JOIN Second_table_name ON First_table_name.column_name= Second_table_name.column_name
Consider the following table for this exercise
Users
Firstname | Lastname | Salary | DeptID |
---|---|---|---|
John | Smith | 1000 | 1 |
Mathew | Simon | 3000 | 1 |
Bill | Steve | 2200 | 1 |
Amanda | Rogers | 1800 | 2 |
Steve | Hills | 2800 | 2 |
Steve | jobs | 2400 | 2 |
bill | cosby | 700 | 3 |
Departments
DeptID | DepartmentName |
---|---|
1 | Employee |
2 | Management |
3 | Staff |
Example # 1
SELECT Firstname, Lastname, Salary, DepartmentName FROM Users INNER JOIN Departments ON Users.DeptID = Departments.DeptID
Result of the Query
Firstname | Lastname | Salary | DepartmentName |
---|---|---|---|
John | Smith | 1000 | Employee |
Mathew | Simon | 3000 | Employee |
Bill | Steve | 2200 | Employee |
Amanda | Rogers | 1800 | Management |
Steve | Hills | 2800 | Management |
Steve | jobs | 2400 | Management |
bill | cosby | 700 | Staff |
We have joined the two tables and matching the primary keys and the foriegn keys from both tables. But of course the column name is not bound to primary keys and foreign. You could link other column as well.
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