Question

For following tables, I’d like to select all users and their groups for a specific account.

USERS 
-id
-name
-groupid
-accountid


GROUPS 
-id
-name
-accountid

I’m doing the following:

SELECT 
USERS.ID,
USERS.NAME,
GROUPS.ID,
GROUPS.NAME,    
FROM GROUPS JOIN USERS ON USERS.ACCOUNTID= GROUPS.ACCOUNTID
WHERE GROUPS.ACCOUNTID=1

For some reason results are repeated 3 times(which is the number of group). Each user is displayed 3 times with different GROUPID.

update If I join on GROUPID instead, like it was suggested. I get the following. As you can see only a single user is displayed per group even though there are more than one user in a group.

USER_ID  GROUP_ID     GROUP_NAME        NAME
42            6        Teacher      John E. 
59            8        Student      Bill W. 

Answer 1

Each User is displayed 3 times with different GROUPID due to you join on the ACCOUNTID instead of GROUPID.

You could try the below ie join on the GROUPID.

SELECT 
USERS.ID,
USERS.NAME,
GROUPS.ID,
GROUPS.NAME    
FROM USERS JOIN GROUPS ON USERS.GROUPID= GROUPS.ID
WHERE GROUPS.ACCOUNTID=1

UPDATED:
http://sqlfiddle.com/#!2/3afee/1