Question

I have been trying to figure out this query for a few hours now without success.

I have 3 tables:
– jstyle_category
– style
– subsite_style_alias

the tables have this schema:

• jstyle_category:
  • style_id
  • category_id
  • subsite_id (INT)
  • sort_order
  • active (ENUM: y,n)
• style
  • id
  • subsite_id (STRING, comma separated)
  • active (ENUM: y,n)
  • currently_available_for_sale (ENUM: y,n)
  • style_type_id
  • date_active (DATETIME)
• subsite_style_alias
  • style_id
  • pos
  • show
  • subsite_logo_group_id
  • subsite_id (INT)

The records are something like

• jstyle_category
  • 1234, 27, 572, 0, y
  • 8800, 27, 572, 1, y
  • 8800, 23, 953, 0, y
  • 8500, 23, 572, 0, y
• style
  • 1234, 572, y, y, 99, 0000-00-00
  • 8800, 123, y, y, 99, 0000-00-00
  • 8500, 572, y, y, 99, 0000-00-00
• subsite_style_alias
  • 8800, 0, y, 2589, 572
  • 8800, 1, y, 3475, 572
  • 8800, 1, y, 9554, 368

what I need a subset that contains all the items in jstyle_category where category_id = 27 with the data from subsite_style_alias if present (and this part I have done it with the following query). My Real problem is that currently I am getting something like:

• 27, 0, 1234, NULL, NULL
• 27, 0, 8800, 0, 2589
• 27, 1, 8800, 1, 3475

What I need is the 8800 where there is no corresponding subsite_style_alias, so the final result will be

• 27, 0, 1234, NULL, NULL
• 27, 1, 8800, NULL, NULL
• 27, 0, 8800, 0, 2589
• 27, 1, 8800, 1, 3475

I know I am close to the answer, I just can’t figure it out.

I am also trying to avoid Unions if possible and rather use joins of the same tables

SELECT  jstyle_category.category_id category_id,
    jstyle_category.sort_order category_pos,
    style.id style_id,
    subsite_style_alias.pos pos,
    subsite_style_alias.subsite_logo_group_id
FROM  `jstyle_category` 
    LEFT JOIN style ON style.id = jstyle_category.style_id
    LEFT JOIN subsite_style_alias ON style.id = subsite_style_alias.style_id AND subsite_style_alias.subsite_id = 572
WHERE 
(

    (
        style.subsite_id = ""  OR 
        FIND_IN_SET("0",style.subsite_id) OR 
        FIND_IN_SET("572",style.subsite_id)
    ) AND 

    (
        subsite_style_alias.`active` = "y"  OR 
        subsite_style_alias.`active` IS NULL 
    ) AND 
    style.active = "y"  AND 
    style.currently_available_for_sale = "y"  AND 
    style.style_type_id NOT IN (7,10,11)  AND 
    jstyle_category.category_id = 27  AND 
    jstyle_category.subsite_id IN (0,572)  AND 
    jstyle_category.active = "y"  AND 

    (
        style.date_active IS NULL  OR 
        style.date_active <= "2012-02-24 18:00:00" 
    )
)
GROUP BY subsite_style_alias.subsite_logo_group_id,
    style.id
ORDER BY category_pos, subsite_style_alias.pos IS NULL,
    subsite_style_alias.pos,
    style.id

Thank you

Answer 1

I solved by adding a new table formed by just NULL and then adding extra logic in the WHERE