如何使用 PHP 从一对多 sql 关系中检索数据

Question

I have two tables. One is called "employee" and has a column named "role". I have another table with the name "role" that has two columns in it "role_id" and "name".

I have linked the two in MySQL with a foreign key (I think,). by going to relationship view through phpmyadmin and selecting the appropriate settings.

Now in PHP I have the following code:

$employees = "SELECT employee_id, first_name, last_name, role 
                 FROM employee 
                 WHERE status = 1"; 
$employee = mysqli_query($link, $employees);

foreach ($employee as $employeeInfo) {
    <?php echo $employeeInfo['role'];?>
}

However, this returns the number I have assigned to the role in the employee's table. Not the name from the linked table.

I think it has something to do with having to use the JOIN condition is the PHP code. However, doing some experimentation just gets me blank results.

Do you have any tips for outputting the role name from the second table in this case?

Thank you

Answer 1

Use join to get the name of the role.

$employees = "SELECT a.employee_id, a.first_name, a.last_name, b.name as role 
                 FROM employee a join role b on a.role = b.role_id
                 WHERE a.status = 1"; 
$employee = mysqli_query($link, $employees);

foreach ($employee as $employeeInfo) {
    echo $employeeInfo['role'];
}

Answer 2

Inner Joins should really work...

SELECT employee_id, first_name, last_name, role.name as role 
    FROM employee 
    INNER JOIN role ON employee.role = role.role_id 
    WHERE status = 1;