MySQL JOIN查询在不同的数据库上给出不同的结果

Question

I'm running an query on my database locally installed on my machine and getting a result different to one when ran on my AWS RDS database. I am running:

SELECT SUM(Hours) AS 'TotalHours', Username, Name, Project_Name, Project_Ref, (37.5-SUM(Hours)) AS 'Missing'  
FROM bookings b 
JOIN projects p ON b.Project_ID=p.Project_ID 
RIGHT JOIN users u ON b.User_ID=u.User_ID   
WHERE  ((Date BETWEEN '2017-07-01' AND '2017-07-30') OR Date IS NULL) 
GROUP BY u.User_ID

When ran on local I get back every entry from the users table, even if they haven't made a booking on the bookings table.

When ran on my server database I only get back users who have made a booking, not ever entry like expected when doing a right join.

Answer 1

Try using LEFT JOIN instead of RIGHT JOIN , and put the Date criteria in the ON clause:

SELECT SUM(Hours) AS 'TotalHours', Username, Name, Project_Name, Project_Ref, (37.5-SUM(Hours)) AS 'Missing'  
FROM users AS u
LEFT JOIN bookings AS b ON b.User_ID = u.User_ID AND b.DATE BETWEEN '2017-07-01' AND '2017-07-30'
LEFT JOIN projects AS p ON b.Project_ID=p.Project_ID

I suspect the problem is related to the INNER JOIN with projects in between the users and bookings table.