Show all content from one table and only matching from the other

Question

I have two tables, "CategoriesTable" and "CompanyTable" I need to show all the entries from the categories table and only the entry (in the category_b in the company table.

    $result = mysqli_query($conn,"SELECT * FROM categories INNER JOIN company ON categories.category = company.category_b WHERE id_com=". $id );

CategoriesTable        CompanyTable

category                category_b
----------------        ----------------
Vendor                  Client
Employee
Client
Prospect   

This is within a drop down menu where the current category stored in the CompanyTable.category_b should show first. If the user wants to change the category the drop down will display the available categories in the category table.

This query only shows the matching entries between each table, so it only displays "Client".

Answer 1

尝试

SELECT * FROM categories LEFT JOIN company ON categories.category = company.category_b WHERE id_com=". $id