多个表上的内部联接不返回行

Question

Is there anything wrong with this query? I was all working until I have Truncated my database and now I have only one record in it and when I run this query in phpmyadmin it returns 0 rows.

What am I missing?

SELECT 
Users.id,
Users.firstname,
Users.lastname,
Users.email,
Users.age,
Users.phone,
Universities.Faculty AS university,
Internship.internship_type AS Internship,
City.city AS city,
Interest.interest AS interest,
Users.filename,
Users.reg_date 
        FROM Users 
        INNER JOIN City ON Users.city = City.key 
        INNER JOIN Universities ON Users.university = Universities.id 
        INNER JOIN Interes ON Users.interest = Interest.key 
        INNER JOIN Internship ON Users.internship_type = Internship.internship_type
            ORDER BY `Users`.`id` ASC;

Answer 1

There might not be data in all the tables so can you check it by using left join and be sure at least user table must have data: then one by one change left join to inner where you won't get data there will be the problem but if other table's data is optional then it's better to use left join:

SELECT 
    Users.id,
    Users.firstname,
    Users.lastname,
    Users.email,
    Users.age,
    Users.phone,
    Universities.Faculty AS university,
    Internship.internship_type AS Internship,
    City.city AS city,
    Interest.interest AS interest,
    Users.filename,
    Users.reg_date 
FROM Users 
LEFT JOIN City ON Users.city = City.key 
LEFT JOIN Universities ON Users.university = Universities.id 
LEFT JOIN Interes ON Users.interest = Interest.key 
LEFT JOIN Internship ON Users.internship_type = Internship.internship_type
ORDER BY `Users`.`id` ASC;