MYSQL SELECT使用或不使用外键从两个表中获取行

Question

I am looking for some help with a MYSQL query. I have two tables, one contains a list of tickets and the other is a list of members .

Table Tickets: ticket_id, member_id Table Members: member_id

A member can but doesn't have to be assigned to a ticket. What I would like to do is select all the tickets and then if the member_id field is set in the tickets table fetch the member information as well.

One approach is to do a SELECT * FROM Tickets and then loop through in PHP and check if the member_id field is set. If set then do another query on the members table to fetch the corresponding information. The only problem with this is that it would be a large number of queries.

Is there any way to fetch all the results in one join query?

Thanks

Answer 1

Select *
from Tickets
Left Join Members On tickets.member_id = members.member_id

Answer 2

select * from tickets left outer join members on tickets.member_id = members.ticket_id

Answer 3

SELECT t.ticket_id, t.member_id FROM tikcets t LEFT JOIN members m ON t.member_id = m.member_id

This will give you all the tickets whether they have been assigned to a member or not. You should add to the query the additional fields that you want to fetch.

Answer 4

Try this:

SELECT t.ticket_id, m.member_id
FROM tickets AS t LEFT OUTER JOIN members AS m 
ON t.member_id = m.member_id

The LEFT OUTER JOIN will cause all results from tickets to be returned, and any match from members, not disqualifying the ticket records, so this could do the trick.