Question

I have a small problem with an SQL statement with a GROUP_CONCAT.

I have this statement:

SELECT ni.*, GROUP_CONCAT(newsletter_item_receivers.value) AS receivers, nf.*, GROUP_CONCAT(nm.mailgroup_name) AS mailgroups
FROM newsletter_items ni
INNER JOIN newsletter_fields nf ON (nf.field_letter_uid = ni.letter_id)                                                          
LEFT JOIN newsletter_item_receivers ON (newsletter_item_receivers.letter_id = ni.letter_id)
INNER JOIN newsletter_mailgroups nm ON (FIND_IN_SET(nm.mailgroup_id, newsletter_item_receivers.value))
WHERE nf.field_name = 'letter_headline' AND ni.template = '". $template ."' 
GROUP BY ni.letter_id

I have done something wrong, because my output is messed up.

I have 4 tables:

newsletter_items that have these columns:

letter_id (int)
letter_date (int)
template (varchar)
status (int)

and newsletter_item_receivers
that have these columns:

rid (int)
letter_id (int)
value (int)

newsletter_mailgroups

mailgroup_id (int)
mailgroup_name (varchar)

newsletter_fields

field_uid (int)
field_name (varchar)
field_content (text)
field_letter_uid (int)

I get almost the output that I want, but my mailgroups are displayed wrong. I want it to be displayed like

Group A, Group C but it is displayed like

Group A, Group C, Group A, Group C, Group C
when my newsletter_item_receivers tables contains this:

rid | letter_id | value
1   | 1         | 2
2   | 1         | 3
3   | 2         | 1

newsletter_item_receivers.letter_id refers to newsletter_items.letter_id and
newsletter_item_receivers.value refers to newsletter_mailgroups.mailgroup_id

Is there someone who can see what I have done wrong?

Answer 1

Try this :-

group_concat( DISTINCT newsletter_item_receivers.value 
              ORDER BY newsletter_item_receivers.value)

And

group_concat( DISTINCT nm.mailgroup_name 
              ORDER BY nm.mailgroup_name)