Mysql Remove Duplicates on Left Join 3 Tables using id - php

Question

I have the following tables
hobbies
+----+-------------+---------------+
| id | employeeid | hobby_name |
+----+-------------+---------------+
| 1 | 123 | cooking |
| 2 | 123 | painting |
| 3 | 124 | dancing |
+----+-------------+---------------+
nonacad_recog
+----+-------------+---------------+
| id | employeeid | recog_name |
+----+-------------+---------------+
| 1 | 123 | Award1 |
| 2 | 123 | Award2 |
| 3 | 124 | Award3 |
+----+-------------+---------------+
org_membership
+----+-------------+---------------+
| id | employeeid | recog_name |
+----+-------------+---------------+
| 1 | 123 | Boyscout |
| 2 | 124 | Girlscout |
+----+-------------+---------------+
This is the query I used:
SELECT h.hobby_name,r.recog_name,o.org_name
FROM hobbies as h
JOIN nonacad_recog as r ON (h.employeeid=r.employeeid)
JOIN org_membership as o ON (r.employeeid=o.employeeid)
WHERE h.employeeid='123'
I am getting duplicate outputs:
+----+-------------+---------------------+
| hobby_name | recog_name | org_name |
+----+-------------+---------------------+
| cooking | Award1 | Boyscout |
| cooking | Award2 | Boyscout |
| painting| Award1 | Boyscout |
| painting| Award2 | Boyscout |
+----+-------------+---------------------+
What I want as an output is like this: with no duplicates
+----+-------------+---------------------+
| hobby_name | recog_name | org_name |
+----+-------------+---------------------+
| cooking | Award1 | Boyscout |
| painting| Award2 | NULL |
+----+-------------+---------------------+
also giving a null to the other columns/rows if there is nothing to return.
I might have missed out some things.
Is this possible to achieve using mysql queries?
Any solution to this?
If I get the correct table, it will be easy for me to
mysqli_fetch assoc the results and display it on a table using PHP.

Answer 1

The problem is that in the desired output you want to relate rows in your tables by non-existent column, which is a row number.
You can technically do it like this
SELECT MAX(CASE WHEN source = 1 THEN name END) hobby_name,
MAX(CASE WHEN source = 2 THEN name END) recog_name,
MAX(CASE WHEN source = 3 THEN name END) org_name
FROM
(
SELECT 1 source, id, hobby_name name, #n1 := #n1 + 1 rnum
FROM hobbies CROSS JOIN (SELECT #n1 := 0) i
WHERE employeeid = 123
UNION ALL
SELECT 2 source, id, recog_name, #n2 := #n2 + 1 rnum
FROM nonacad_recog CROSS JOIN (SELECT #n2 := 0) i
WHERE employeeid = 123
UNION ALL
SELECT 3 source, id, org_name, #n3 := #n3 + 1 rnum
FROM org_membership CROSS JOIN (SELECT #n3 := 0) i
WHERE employeeid = 123
ORDER BY source, id
) q
GROUP BY rnum
Output:
| HOBBY_NAME | RECOG_NAME | ORG_NAME |
|------------|------------|----------|
| cooking | Award1 | Boyscout |
| painting | Award2 | (null) |
Here is SQLFiddle demo
Here is an alternative solution. You pack all values as delimited strings with GROUP_CONCAT()
SELECT GROUP_CONCAT(DISTINCT hobby_name ORDER BY h.id) hobby_name,
GROUP_CONCAT(DISTINCT recog_name ORDER BY r.id) recog_name,
GROUP_CONCAT(DISTINCT org_name ORDER BY o.id) org_name
FROM
(
SELECT 123 employeeid
) e LEFT JOIN hobbies h
ON e.employeeid = h.employeeid
LEFT JOIN nonacad_recog r
ON e.employeeid = r.employeeid
LEFT JOIN org_membership o
ON e.employeeid = o.employeeid;
Output:
| HOBBY_NAME | RECOG_NAME | ORG_NAME |
|------------------|---------------|----------|
| cooking,painting | Award1,Award2 | Boyscout |
Here is SQLFiddle demo
and then in your client php code easily explode() column values while iterating over the resultset and build your presentation.

Answer 2

I think "Limit" can work:
SELECT h.hobby_name,r.recog_name,o.org_name
FROM hobbies as h,
nonacad_recog as r,
org_membership as o
WHERE h.employeeid='123'
AND r.employeeid=o.employeeid
AND h.employeeid=r.employeeid
LIMIT 1