Getting distinct records from a mysql query

Question

In my application, there are publishers and categories. One publisher can belong to several categories. When I make my mysql transaction, it will return the same publisher record for each category it belongs to. Here's the query:

SELECT
    grdirect_publisher.name,
    grdirect_publisher.short_description,
    grdirect_publisher.thumb_image,
    grdirect_publisher.url,
    grdirect_category.name AS catname
FROM
    grdirect_publisher
JOIN
    grdirect_publisher_categories
    ON
    grdirect_publisher.id = grdirect_publisher_categories.publisher_id
JOIN
    grdirect_category
    ON
    grdirect_publisher_categories.category_id = grdirect_category.id

returns:

name    short_description   thumb_image url catname
------------------------------------------------------------
Foo Lorem Ipsum...      images/pic.png  d.com   Video Games
Foo Lorem Ipsum...      images/pic.png  d.com   Music
Bar Blah Blah...        images/tic.png  e.com   Music

Essentially, Foo should only show up once in the results.

Answer 1

You can use DISTINCT but if any column in your result set has a distinct value, it forces the row to be duplicated. If you want to reduce the list to one row per name , then you have to use DISTINCT and you have to omit the catname column:

SELECT DISTINCT
    grdirect_publisher.name,
    grdirect_publisher.short_description,
    grdirect_publisher.thumb_image,
    grdirect_publisher.url
FROM
. . .

Another solution instead of using DISTINCT is MySQL's aggregate function GROUP_CONCAT() which allows you to take multiple values in a group and produce a comma-separated list:

SELECT
    grdirect_publisher.name,
    grdirect_publisher.short_description,
    grdirect_publisher.thumb_image,
    grdirect_publisher.url,
    GROUP_CONCAT(grdirect_category.name) AS catname
. . .
GROUP BY grdirect_publisher.id;

So you have to decide how you want the result set to look to get the right solution.