I just want to know how to get individual count of same value rows with join using mysql and help are definitely appreciated
Here is my mysql Query
SELECT c.`id`
FROM categories c inner join subcategories sc
on c.`id` = sc.`cat_id`
See the Response screeshot
try this query:
SELECT c.`id`, count(1)
FROM categories c inner join subcategories sc
on c.`id` = sc.`cat_id`
GROUP BY c.`id`
It's quite a basic task. Consider studying GROUP BY and aggregate functions.
SELECT id, COUNT(*)
FROM categories c
INNER JOIN subcategories sn ON c.id = sn.cat_id
GROUP BY c.id
Related
I have below query
select catid, cat_name, currency, count(is_reporting_category_sales.id) as total_sales,
sum(total_sales) as total_earning
from is_category
left join is_reporting_category_sales on is_category.catid = is_reporting_category_sales.category_id
join is_reporting_order on is_reporting_order.id = is_reporting_category_sales.order_id
group by catid, cat_name, currency
ORDER BY `is_category`.`cat_name` ASC
but this is returning only rows that are common in is_category and is_reporting_category_sales, is_reporting_order but I want to fetch all rows from is_category table. And if there is no order for the category then 0 as total_earning and total_sales.
You have to Use Left Join
left join is_reporting_order on is_reporting_order.id = is_reporting_category_sales.order_id
Instead of
join is_reporting_order on is_reporting_order.id = is_reporting_category_sales.order_id
Perhaps using left outer joins you might get the results you expect ( had to guess at some of the aliases for columns btw so some of them might be wrong )
select c.`catid`, c.`cat_name`, `currency`, count(i.`id`) as 'total_sales', sum(`total_sales`) as 'total_earning'
from `is_category` c
left outer join `is_reporting_category_sales` i on c.`catid` = i.`category_id`
left outer join `is_reporting_order` on o.`id` = i.`order_id`
group by c.`catid`, c.`cat_name`, `currency`
order by c.`cat_name` asc;
I wish to join multiple tables like- Categories, menus, restaurants, reviews, etc.
to return the restaurants that provide the inserted food with their prices.
Everything works except numberOfReviews in reviews table.
If a restaurant has no reviews then output should be 0 for numOfReviews column but other column values should be retrieved i.e. price, name, etc.
With following query I get all fields as null and count(numReviews) as 0:
select r.id
,r.`Name`
,r.`Address`
,r.city
,r.`Rating`
,r.`Latitude`
,a.`AreaName`
,m.`Price`
,count(rv.id)
from `categories` c, `menus` m, `restaurants` r, areas a, reviews rv
where m.`ItemName`="tiramisu"
and c.`restaurant_id`=r.`id`
and m.`category_id`=c.id
and r.`AreaId`=a.`AreaId`
and if I can't match rv.restaurant_id=r.id in where clause(obviously).
Where am I getting wrong? How do I solve this?
edited
select r.id,
r.`Name`,
r.`Address`,
r.city,
r.`Rating`,
r.`Latitude`,
a.`AreaName`,
m.`Price`,
r.`Longitude`,
r.Veg_NonVeg,
count(rv.id)
from restaurants r LEFT JOIN `reviews` rv on rv.`restaurant_id`=r.`id`
inner join `categories` c on c.`restaurant_id` = r.id
inner join `menus` m on m.`category_id` = c.id
inner join `areas` a on a.`AreaId` = r.`AreaId`
where m.`ItemName`="tiramisu"
First of all, don't use this old school syntax for the jointures.
Here is a query that may solve your problem:
SELECT R.id
,R.Name
,R.Address
,R.city
,R.Rating
,R.Latitude
,R.Longitude
,A.AreaName
,M.Price
,R.Veg_NonVeg
,COUNT(RV.id) AS numOfReviews
FROM restaurants R
INNER JOIN categories C ON C.restaurant_id = R.id
INNER JOIN menus M ON M.category_id = C.id
INNER JOIN areas A ON A.AreaId = R.AreaId
LEFT JOIN reviews RV ON RV.restaurant_id = R.id
WHERE M.ItemName = 'tiramisu'
GROUP BY R.id, R.Name, R.Address, R.city, R.Rating, R.Latitude, R.Longitude, A.AreaName, M.Price, R.Veg_NonVeg
I used explicit INNER JOIN syntax instead of your old school syntax and I modified the jointure with table reviews in order to get the expected result. The GROUP BY clause is required to use the aggregate function COUNT, every rows will be grouped by the enumerated columns (every column except the one used by the function).
Here is another solution that simplify the GROUP BY clause and allow the modification of SELECT statement without having to worry about the fact that every columns need to be part of the GROUP BY clause:
SELECT R.id
,R.Name
,R.Address
,R.city
,R.Rating
,R.Latitude
,R.Longitude
,A.AreaName
,M.Price
,R.Veg_NonVeg
,NR.numOfReviews
FROM restaurants R
INNER JOIN (SELECT R2.id
,COUNT(RV.id) AS numOfReviews
FROM restaurants R2
LEFT OUTER JOIN reviews RV ON RV.restaurant_id = R2.id
GROUP BY R2.id) NR ON NR.id = R.id
INNER JOIN categories C ON C.restaurant_id = R.id
INNER JOIN menus M ON M.category_id = C.id
INNER JOIN areas A ON A.AreaId = R.AreaId
WHERE M.ItemName = 'tiramisu'
As you can see here I added a new jointure on a simple subquery that does the aggregation job in order to provide me the expected number of reviews for each restaurant.
Hope this will help you.
I searched lots of similar topics about this but can't find the answer to this specific probem.
So I have a table with categories and I have another table with products, so what I want is select all the categories that contain at least 1 product, seems very easy but the following code dont give me what I expect.
SELECT *
FROM categories
INNER JOIN products on (categories.id = products.cat_id)
HAVING count(products.cat_id) > 0
All help is appreciated.
Thank you!
You can actually get what you want with just a join because any categories without products will not match.
You should also add a DISTINCT or GROUP BY to remove the duplicate category records from the results:
SELECT DISTINCT c.*
FROM categories c
JOIN products p
ON c.id = p.cat_id
OR:
SELECT c.*
FROM categories c
JOIN products p
ON c.id = p.cat_id
GROUP BY c.id
If you want something fancy like categories that have 2 or more products then you can use GROUP BY and HAVING:
SELECT c.*
FROM categories c
JOIN products p
ON c.id = p.cat_id
GROUP BY c.id
HAVING count(*) >= 2
Try this select in this select all categories that have at least one product
select categories.* from categories
left join products on (categories.id = products.cat_id)
where products.cat_id IS NOT NULL
group by categories.id
In this case you're not using "HAVING" but will have the same result
This code only shows categories with articles in them.
I want to show all categories.
Pls help.
$query = "SELECT C.id, C.jcat_name,COUNT(A.catid) AS catid FROM jt_categories C INNER JOIN jt_articles A ON C.id = A.catid GROUP BY C.id";
change to left join
SELECT C.id, C.jcat_name,COUNT(A.catid) AS catid FROM jt_categories C
LEFT JOIN jt_articles A ON C.id = A.catid GROUP BY C.id
Change INNER JOIN for LEFT JOIN in your query.
INNER JOIN looks explicitely for the join in the data
replace the inner join by a left outer join
Change INNER JOIN to LEFT JOIN.
Did u try LEFT JOIN ? bc. (i think) in second table u have NULL articles for some categories.
I'm really sorry for the first post as i didn't explain everything.
Basically i have 3 tables, One for posts, One for Categories, & Another to link categories with posts.
I want in a single MySQL query to select posts that are under a specific category.
posts(id,title,body)
---------------------
125,Some title,Blah blah
categories(id,name)
---------------------
1,politic
2,entertainment
linker(categoryid,postid)
---------------------
2,125
I want in single query to fetch posts in the entertainment category by example, what to do?
Thanks
select
p.*
from
posts p
inner join linker l on l.postid = p.id
inner join categories c on c.categoryid = l.categoryid
where
c.name = 'entertainment'
The following SQL statement should provide you with a basis for what you are trying to do.
select p.*
from posts p
inner join linker l
on l.postid = p.id
inner join categories c
on l.categoryid = c.id
where c.name = 'entertainment'
If a post belongs to 2 categories, you can still use pinkfloydx33's query with DISTINCT in the select statement:
select
DISTINCT p.*
from
posts p
inner join linker l on l.postid = p.id
inner join categories c on c.categoryid = l.categoryid
where
c.name = 'entertainment'
The result set will show only one record.
It's the same exact thing, you just have to join 3 tables intead of 2 :
SELECT P.id post_id,
P.title,
P.body,
C.id category_id,
C.name
FROM posts P
INNER JOIN linker L
ON P.id = L.postid
INNER JOIN categories C
ON L.categoryid = C.id
WHERE C.name = 'Category'
Don't be afraid to do your own tests. If you understand how to join two tables, you should understand how to join three, four and more.
If you are specifying only one category in the WHERE clause, then the result will be a single row for each post ID.
Either way you can use DISTINCT or GROUP BY when the result could be more than one row per ID, but in that case i prefer the second one (GROUP BY).