Topic: Mulitple INNER JOIN's

[pengu]

Hello all, haven't posted for a while.

I did a quick search on this and found it for MySQL.

So I want to do something like..

Code: [Select]


SELECT table1.id, table1.info, table2.description, table3.example FROM table1 INNER JOIN table2 ON table1.id = table2.id


That much works, but not sure how to or if it is even possible to do another INNER JOIN.

Thank you for help!

[Mchl]

Yes, it is possible to have multiple JOINS in one query. Just make sure your syntax is correct.

[pengu]

Could you give me a little example of the correct syntax?

[Mchl]

Code: [Select]

SELECT
  t1.id, t1.info,
  t2.description,
  t3.example
FROM
  table1 AS t1
INNER JOIN
  table2 AS t2
ON
  t1.id = t2.id
INNER JOIN
  table3 AS t3
ON
  t2.id = t3.id


[pengu]

Bah.. this is what I did, the 'AS' is not needed, right?  It's just a mask for table name sort of thing?

Thanks for response anyways.

[gizmola]

Bah.. this is what I did, the 'AS' is not needed, right?  It's just a mask for table name sort of thing?

Thanks for response anyways.

Yes it's optional, it aliases the table, so that you don't have to spell out the full table name all the time.  There are also times when you require an alias -- namely when you are joining a table to itself.

[Mchl]

Also if you're joining a subquery rather than actual table, you have to give it an alias.

Code: [Select]

SELECT
  t1.ID, t1.field1,
  sq.field2, sq.field3
FROM
  table1 AS t1
INNER JOIN (
  SELECT
     ID, field2, field3
  FROM
    someOtherTable
  WHERE
    someCondition = TRUE
) AS sq
ON
  t1.ID = sq.ID


[pengu]

Thanks for the help guys.

Found the problem, I was editing a report created by someone else and some of the field names didn't have the table prefix at the front and it was clashing with the other tables.  All good now!

Solved.