I have a table in database for categories and sub categories. Its internal structure is:
id int not null primary
name text
subcatfrom int
it contains some of rows for categories and its sub categories. I want "SELECT" sql command to fetch categories and grouping their sub categories after it for every root category as following for example :
-cat1
--subcat1
--subcat2
-cat2
--subcat1
--subcat2
is it possible ?
The original question wants the subcategories on separate rows. Here is one way:
select name
from ((select category as name, 1 as iscat, category as sortorder
from t
) union all
(select tsub.category as name 0 as iscat, t.category as sortorder
from t join
tsub on
on t.subcategory_id = s.category_id
)
) a
where not exists (select 1 from category c where c.subcategory_id = a.sortorder limit 1)
order by sortorder, iscat desc, name
What is this doing? The inner union all is bringing together all categories and subcategories. It is assigning what you want in the table as well as information for sorting. The overall ordering is by "parent" category name.
The where clause is limiting this data to categories that are not the subcategory of anything else -- the top level categories.
I am making the assumptions that-
1. you have just one level of parent child relationship. ie subcategory can't have further sub-category
2. For top level category, value of subcatfrom is 0
SELECT * FROM
(
SELECT NAME AS parent_category_name, '' AS child_category_name FROM categories WHERE subcatfrom = 0
UNION
SELECT b.NAME AS parent_category_name, a.NAME AS child_category_name FROM categories a JOIN categories b ON a.subcatfrom = b.id
) a ORDER BY a.parent_category_name, a.child_category_name;
That's very easy but with this structure
Table: category_id , name , parent_id
Sample Data
category_id name parent_id
1 A 0
2 B 0
3 C 1
4 D 1
This means A is a category which has 2 subcategories C and D. And parent_id 0 means it is a parent category
Now the sql is
SELECT lc.category_id,
lc.name,
rc.subcategories
FROM categories
LEFT JOIN (
SELECT
subcategory_id ,
GROUP_CONCAT(name) AS subcategories
FROM categories) AS rc
ON lc.category_id = rc.parent_id
This will give you the following result
category_id name subcategories
1 A C,D
2 B (null)
Related
I am trying to get the category name from categories linkt with a retailer_id and category_id
These are the three tables:
1)retailers,
retailer_id
2)retailer_to_category,
retailer_id and
category_id
3)categories,
category_id and
name
I want to select the (categories) name.
I tried many options but nothing seems to help.
$query = "
SELECT s.name
, c.retailer_id
, b.retailer_id
FROM categories s
JOIN retailer_to_category b
ON s.category_id = b.category_id
JOIN retailers c
ON b.retailer_id = c.retailer_id
";
But that only displays the first category name in the database table, whichever retailer I select
Structure of the Category table:
id
title
parent_id
Structure of the Item table:
id
title
is_active (0 или 1)
category_id
table structure
Tables are associated with the category_id field by a one-to-many relationship. Those. 1 category can have many items.
The two-level hierarchy in the Category table. This defines the main categories and subcategories. Categories are those records in which parent_id = NULL. And subcategories, these are those records in which parent_id = to some id.
One Item can belong to both the main category (where parent_id = null) and the subcategory (child). Item can be active and not active (0 or 1).
You need to make a query and select from the Category table all the main categories (which have parent_id = null) that have active items (is_active = 1) and which have subcategories also with active itemes.
i.e If the child subcategory has items with is_active = 0, then do not display this category.
I could only choose the main categories in which only active items:
SELECT categories.title, count(analyses.id) FROM items
INNER JOIN categories on items.category_id = categories.id
WHERE categories.parent_id IS NULL
AND categories.is_active = 1
GROUP BY analyses.category_id
ORDER BY analyses_categories.title
But with subcategories can not cope anymore, tell me please who has more experience.
It's a little unclear what you are trying to count (just the active items associated with the parent?), but I would use exists to find out which have children with active items as well:
select c.title, count(*)
from categories c
join item i on i.category_id = c.id
where c.parent_id is null and i.is_active = 1 and exists (
select 1
from categories c2
join item i on c2.id = i.category_id
where c2.parent_id = c.id and i.is_active = 1
)
group by c.title
I have a products database which has a multi-tier category structure. Products are assigned to a category. The category table looks like this:
id name parent_id
================================
1 Electronics NULL
2 AV 1
3 Speakers 2
4 Wireless 3
What I want to do is, as part of my SELECT statement for products, output a concatenated string of the category tree.
The product is always assigned to the last category, so for example, Product "500w Wireless Speakers" would be assigned to category_id 4 (based on the above).
The ouputted column should be Electronics-AV-Speakers-Wireless.
Is this possible to do? I have looked at GROUP_CONCAT() but I'm having trouble working out the correct syntax.
Join as many times as you need, and concat the names:
select concat(a.name, '-', b.name, '-', c.name, '-', d.name) name
from mytable a
join mytable b on a.id = b.parent_id
join mytable c on b.id = c.parent_id
join mytable d on c.id = d.parent_id;
i have two tables
Table1 : Categories ,
Columns : id , parent_id , name
Table2 : products ,
Columns : id , product_name , category_id , subcategory_id , sale_wanted
Here is the detail
A category can have multiple subcategories id. Parent id 0 means it s a category and parent id != 0 means it is a subcategory. Now each product is related to a subcategory. I need to display the names of category and total subcategories count related to each category.
sale 0 means the product is for sale and 1 means it is required.
Now i need this.
1.Display all categories and count of subcategories related to each category where the products related to category are for sale.
The problem it is that your structure is recursive.
I think you can search for more informations about intervallic representation.
Well i have found this solution
select
dc.category_id,
dc.name ,
count(ldc.name) as total
from default_category as dc
inner join default_category as ldc on ldc.parent_id= dc.category_id
inner join(select * from default_products where sale_wanted = 1) as dp on dp.subcategory_id = ldc.category_id
where dc.parent_id = 0
group by dc.category_id
This works well.
I have a MYSQL table called 'categories' from a project I inherited from someone else.
id parent_id name
1 NULL Travel
2 NULL Sleep
3 NULL Eat
4 NULL Bath
5 1 Prams
6 1 Travel Systems
7 2 Cots
8 3 High Chairs
The table is obviously a lot bigger than that, but you get the general idea. I have a MYSQL statement which brings together this table with other category, brand and product tables, but basically I want to list the parent category name from the above table with the sub-category in the statement. How do I do this?
My current statement is something like:
SELECT brands.name, products.name, categories.id, categories.name, brands.id,
FROM `products` , `brands` , `categories`
WHERE products.brand_id = brands.id
AND products.category_id = categories.id
AND brands.name = '$brand'
ORDER BY categories.name, products.name
How do I retrieve the parent category names in the results?
For example if the product is a Pram, how can I output "Travel". I could do seperate MYSQL statements in the loop but I want to avoid this. This is either a stupidly simple question (in which case I apologise for being brain dead) or a little more complicated! Thanks.
First you need to know the parent id of the current category and then get the name for that id, you could use a subquery in this way:
SELECT name FROM categories WHERE id = (SELECT pid FROM categories WHERE name = $brand)
EDIT: Since you need to get the category and subcategory names in the same row for a given subcategory id, try this:
SELECT sc.name AS subcategory, c.name AS category
FROM categories sc
LEFT JOIN categories c ON c.id = sc.parent
WHERE sc.id = $subcategory_id