?
Solved

How Do I Write a Multiple Inner Join?

Posted on 2009-07-04
4
Medium Priority
?
264 Views
Last Modified: 2012-05-07
Hi, I know this type of question has been asked and answered many times, and I've looked through numerous threads, but everything I've tried hasn't worked for me.  Obviously, I'm doing it wrong, but I haven't been able to figure it out, so I thought I'd ask it once again.  I apologize in advance.

I have three tables that I need to join in my query, a comments table, a photos table, and a users table.  I need to return a list of comments, the name of the user who made them, and the name of the photo that the comment was made on.

The comments table contains the user id, and the photo id.  Here's the query I have right now, which gets the comment, and the photo title.  I just need to add an inner join to get the user name as well:

$sql="Select * From CmtsSharedPhoto c INNER JOIN sharePhotoFiles p ON cmt_object_id = medID order by cmt_time desc LIMIT 100";

The user id in the comments table is "cmt_author_id", and in the users table (Profiles), the user id is "ID".

If you need anything else, just let me know!  Thanks!!
0
Comment
Question by:sbcjr
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 75

Accepted Solution

by:
Aneesh Retnakaran earned 1400 total points
ID: 24777778
Select *, u.userName From CmtsSharedPhoto c INNER JOIN sharePhotoFiles p ON cmt_object_id = medID
INNER JOIN Profiles u on u.id = c.cmt_author_id
order by cmt_time desc LIMIT 100
0
 
LVL 143

Assisted Solution

by:Guy Hengel [angelIII / a3]
Guy Hengel [angelIII / a3] earned 600 total points
ID: 24777780
this is mysql, right?

you will need to take the habit of:
* avoid using SELECT *. list the columns you really need
* use table_name_or_alias.column_name syntax. make it clean on all the parts of the query where a column comes from

for example:
$sql="Select c.cmt_time CommentTime, c.cmt_text CommentText, p.Name PhotoName, u.name UserName From CmtsSharedPhoto c JOIN sharePhotoFiles p ON c.cmt_object_id = p.medID JOIN users_table u on u.id = c.user_id order by c.cmt_time desc LIMIT 100";

Open in new window

0
 
LVL 1

Author Comment

by:sbcjr
ID: 24777799
Awesome!  I have no idea why I couldn't figure that out.  Thank you both so very much.  You have made my week!
0
 
LVL 1

Author Comment

by:sbcjr
ID: 24777843
@angelIII - Just a follow-up... I made the changes you suggested, and, wow!  That really reduced the loading time of these pages.  Thank you, thank you, thank you!
0

Featured Post

Get MongoDB database support online, now!

At Percona’s web store you can order your MongoDB database support needs in minutes. No hassles, no fuss, just pick and click. Pay online with a credit card. Handle your MongoDB database support now!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

If you have heard of RFC822 date formats, they can be quite a challenge in SQL Server. RFC822 is an Internet standard format for email message headers, including all dates within those headers. The RFC822 protocols are available in detail at:   ht…
This post looks at MongoDB and MySQL, and covers high-level MongoDB strengths, weaknesses, features, and uses from the perspective of an SQL user.
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
In this brief tutorial Pawel from AdRem Software explains how you can quickly find out which services are running on your network, or what are the IP addresses of servers responsible for each service. Software used is freeware NetCrunch Tools (https…
Suggested Courses
Course of the Month9 days, 12 hours left to enroll

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question