CODEWITHSUNDEEP
mysqlgroup-concat
newbie-shame
newbie-shame

Reputation: 243

Mysql Group_Concat function

Not understanding how to use the GROUP_CONCAT function as my queries seem to repeat values that I don't actually want.

I have three tables:

------------------
Content
------------------
cid | title
2334 | Lorem Ipsum

------------------
Organizers
------------------
cid | name | sort
2334 | John Doe | 0

------------------
Participants
------------------
cid | name | sort
2334 | Jane Doe | 0
2334 | Bob Hope | 1
2334 | Bart Simpson | 2

I'm trying to write a query that will produce:

cid | title | organizers | participants
2334 | Lorem Ipsum | John Doe | Jane Doe, Bob Hope, Bart Simpson

So, I'm trying to use GROUP_CONCAT. But, values are being repeated, so I'm not sure how to output the results I'm looking for? 

SELECT GROUP_CONCAT(co.name) as organizers, 
GROUP_CONCAT(cp.name) FROM content n 
LEFT JOIN organizers co ON n.cid = co.cid 
LEFT JOIN participants cp ON n.cid = cp.cid 
WHERE n.cid = 2334

The above yields:

cid | title | organizers | participants
2334 | Lorem Ipsum | John Doe, John Doe, John Doe | Jane Doe, Bob Hope, Bart Simpson

Upvotes: 0

Views: 2071

Answers (2)

Tony
Tony

Reputation: 838

SELECT n.cid, n.Title,
  GROUP_CONCAT(DISTINCT co.name ORDER BY co.sort) as organizers, 
  GROUP_CONCAT(cp.name ORDER BY cp.sort) 
FROM Content n 
LEFT JOIN Organizers co ON n.cid = co.cid 
LEFT JOIN Participants cp ON n.cid = cp.cid 
GROUP BY n.cid

Upvotes: 1

ajreal
ajreal

Reputation: 47331

select group_concat(distinct co.name)

details : http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

syntax

GROUP_CONCAT([DISTINCT] expr [,expr ...]
[ORDER BY {unsigned_integer | col_name | expr}
[ASC | DESC] [,col_name ...]]
[SEPARATOR str_val])

Upvotes: 2

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