Help me pls.
I have 3 tables:
users
id rating
posts
id_post rating id_author
photos
id_photo rating id_user
Need query for update users rating based on formula: avg(users posts ratings) + avg(user photos ratings).
Tryed this but works only if user have and posts and photos. If user have photos, and no posts then ratings become 0:
UPDATE users U
inner JOIN
(select id_user, avg(rating) as avgrating
from photos P
group by id_user
) P
on U.id = P.id_user
inner JOIN
(select author_id, avg(rating) as avgrating_posts
from posts PS
group by author_id
) PS
on U.id = PS.author_id
SET
U.rating = (
P.avgrating +
PS.avgrating_posts
)
UPDATE users SET
rating = (
( SELECT AVG(rating) FROM photos
WHERE photos.id_user = users.id AND deleted = 0 AND hidden = 0 AND date_published > 0 ) +
( SELECT AVG(rating) FROM posts
WHERE posts.author_id = users.id AND published_at > 0
) )
Use left join for your inner queries, so if there are no associated records found for a user a null value will be returned.
UPDATE users U
LEFT JOIN (SELECT author_id,
AVG(rating) AS avgrating_posts
FROM posts PS
GROUP BY author_id) PS
ON U.id = PS.author_id
LEFT JOIN (SELECT id_user,
AVG(rating) AS avgrating
FROM photos P
GROUP BY id_user) P
ON U.id = P.id_user
SET U.rating = COALESCE(P.avgrating,0) + COALESCE(PS.avgrating_posts,0)
Related
I'm building a query that should return the last 10 posts (default ordering) by $userId and the users it is following.
SQL Fiddle with a minimal example of the query: https://www.db-fiddle.com/f/i5ByFAXwADj5pfjCTn1g1m/2
The database structure is pretty simple:
posts (id, root, user, content)
users (id, username)
following (user_id, followed)
This is the query I'm currently using to get all posts:
SELECT posts.id, posts.content, users.id AS user_id, users.username
FROM posts
LEFT JOIN users ON posts.user = users.id
WHERE LIMIT 10
The query is working but it is listing posts from every user without distinction.
This is the query I built to exclude posts from users that $userId is not following, but it doesn't include $userId's own posts:
SELECT posts.id, posts.content, users.id AS user_id, users.username
FROM following
LEFT JOIN posts ON posts.user = '$userId' OR posts.user = following.followed
LEFT JOIN users ON posts.user = users.id
WHERE (following.user_id = '$userId' OR following.user_id = NULL) LIMIT 10
I've tried replacing the LEFT JOIN posts with an INNER JOIN and a RIGHT JOIN with no success whatsoever. I'm not able to find the error, why isn't the query including posts made by $userId?
I have also tried selecting from posts and joining followers, but it is returning duplicated content:
SELECT posts.id, posts.content, users.id AS user_id, users.username
FROM posts
LEFT JOIN following ON following.user_id = '$userId'
LEFT JOIN users ON posts.user = users.id
WHERE (posts.user = '$userId' OR posts.user = following.followed)
LIMIT 10;
I was about to post a UNION solution
SELECT
post_id,
content,
user_id,
username
FROM
(SELECT
posts.id post_id,
content,
users.id user_id,
username
FROM
posts INNER JOIN
users
ON user = users.id
UNION SELECT
posts.id,
content,
users.id,
username
FROM
posts INNER JOIN (
following INNER JOIN
users
ON user_id = users.id
) ON user = followed
) p
WHERE
user_id = 1
LIMIT 10;
Then I saw #Gordon Linoff's solution which might be better - more concise, at least - but I don't think it works as posted.
SELECT
posts.id,
content,
users.id,
username
FROM
posts INNER JOIN
users
ON user = users.id
WHERE
users.id = 1
OR EXISTS (
SELECT
*
FROM
following
WHERE
followed = user
AND user_id = 1
)
LIMIT 10;
Get the posts from the table posts under your conditions and join to users:
select p.id, p.content, u.id AS user_id, u.username
from (
select *
from posts
where user = '$user_id'
or user in (select user_id from following where followed = '$user_id')
) p inner join users u on u.id = p.user
order by p.id desc limit 10
Note that as it is your requirement the results may not contain posts by the user '$user_id' if the last 10 posts are from the users that this user follows.
See the demo.
I'm building a query that should return the last 10 posts by $userId and the users it is following.
So, there are two tasks here:
Get first N records per group
Apply query to given user PLUS the same for the related users
I would do something like this (pseudo code):
ids = query('SELECT user_id FROM following WHERE followed = :id)', userId).pluck('user_id');
ids.push(userId);
SELECT x.id, x.user_id, x.content
FROM (
SELECT #num := IF(#id = user_id, #num + 1, 1) AS num,
#id := posts.user_id as x_user_id,
posts.*
FROM
(SELECT #num := null, #id := null) x,
posts
WHERE posts.user_id IN(:ids)
ORDER BY posts.id DESC
) AS x
WHERE x.num <= 10
(https://www.db-fiddle.com/f/aiBUwqDApJp6foyq13ZZ2u/1)
See:
S.O.: get first N records per group
S.O.: prepared statement with WHERE IN
If I understand correctly, you basically want an EXISTS clause:
SELECT p.id, p.content, u.id AS user_id, u.username
FROM posts p JOIN
users u
ON p.user = u.id
WHERE u.id <> ? -- ? is the userid AND
EXISTS (SELECT 1
FROM following f
WHERE f.followed = ? AND
f.user_id = u.id
)
LIMIT 10;
I am running this query in my database:
SELECT * FROM posts INNER JOIN profile ON posts.user_id = profile.user_id
WHERE posts.user_id IN
(SELECT user_id FROM users WHERE class_name IN
(SELECT class_name FROM classroom WHERE created_by = '456'))
OR posts.user_id IN
(SELECT user_id FROM users WHERE role = 'teacher' AND school_name = 'SK Taman Megah')
ORDER BY posts.created_at DESC;
This is my classroom table:
This is my users table:
This is my post table:
This is my profile table:
This is my output:
Expected output should have a total of 4 rows with post_id of (60,57,61,56) but only 2 was shown. Is there a mistake in the SQL query?
I think following one is what you are expecting:
SELECT * FROM posts INNER JOIN profile ON posts.user_id = profile.user_id where posts.user_id IN (select distinct user_id from users left join classroom on classroom.class_name = users.class_name where classroom.created_by='456' or (users.role='teacher' and users.school_name='SK Taman Megah') )
I have two tables one is users and second is user_education.One users can have more than one education listing so i want to get the latest user education listing
users
===============
1-id
2-email
member_experience
==============
1-id
2-user_id
3-designation
user id 1 has 4 enteries in user_education so i want to get the last record enter designation of the user
original full query is like this
SELECT u.id,u.name,u.gender,u.email,file_managed.file_name,file_managed.file_path
from users as u
INNER JOIN member_experience on (SELECT uid FROM member_experience where member_experience.uid=u.id ORDER BY id DESC LIMIT 1)=u.id
LEFT JOIN file_managed on file_managed.id= u.fid
where u.user_type ='individual' AND u.gender='male'
"INNER JOIN member_experience on (SELECT uid FROM member_experience where member_experience.uid=u.id ORDER BY id DESC LIMIT 1)=u.id "
this portion has problem as users has many record in member_experience table but i want to get only one which is latest.
thanks
Devolve the acquisition of the last record to the where statement.
drop table if exists member_experience;
create table member_experience(id int auto_increment primary key, userid int);
insert into member_experience (userid) values
(1),(2),(1);
select * from member_experience
SELECT u.id,m.id
from users as u
join member_experience m on m.userid = u.id
where m.id = (SELECT max(m.id) FROM member_experience m where m.userid = u.id)
order by u.id
Or if you want to include those with no experience
SELECT u.id,m.id
from users as u
left join member_experience m on m.userid = u.id
where (m.id = (SELECT max(m.id) FROM member_experience m where m.userid = u.id)
or m.id is null)
and u.id < 4
order by u.id
I have three tables, users, activities and purchases.
Users has many activities and purchases, activities has 4 types.
I need to query users like this:
[
{
user_id: 1,
// from activities
post_count: 2,
updated_count: 3,
print_count: 4,
share_count: 5,
// from purchases
purchase_count: 6
},
...
]
I use this sql:
SELECT u.id, post.post_count, updated.update_count, print.print_count, share.share_count, purchase.purchase_count
FROM users as u
LEFT JOIN (
SELECT user_id, activity_type, count(*) as post_count
FROM activities
WHERE activity_type = 1
GROUP BY user_id
) post
ON u.id = post.user_id
LEFT JOIN (
SELECT user_id, activity_type, count(*) as update_count
FROM activities
WHERE activity_type = 2
GROUP BY user_id
) updated
ON u.id = updated.user_id
LEFT JOIN (
SELECT user_id, activity_type, count(*) as print_count
FROM activities
WHERE activity_type = 3
GROUP BY user_id
) print
ON u.id = print.user_id
LEFT JOIN (
SELECT user_id, activity_type, count(*) as share_count
FROM activities
WHERE activity_type = 4
GROUP BY user_id
) share
ON u.id = share.user_id
LEFT JOIN (
SELECT user_id, count(*) AS purchase_count
FROM purchases
GROUP BY user_id
) purchase
ON u.id = purchase.user_id
how can i optimize performance with this query?
Great thanks to Eugen Rieck
I modified his query to this, then it works.
SELECT
users.id AS user_id,
SUM(IF((activities.activity_type=1),1,0)) AS post_count,
SUM(IF((activities.activity_type=2),1,0)) AS update_count,
SUM(IF((activities.activity_type=3),1,0)) AS print_count,
SUM(IF((activities.activity_type=4),1,0)) AS share_count,
IFNULL(purchase.count,0) AS purchase_count
FROM
users
LEFT JOIN activities ON activities.user_id=users.id
LEFT JOIN (
SELECT user_id, count(*) AS count
FROM purchases
GROUP BY user_id
) purchase
ON users.id = purchase.user_id
GROUP BY users.id
Currently you run the activities table 4 times - this could be folded into one:
SELECT
users.id AS user_id,
SUM(IF(activites.activity_type=1,1,0)) AS post_count,
SUM(IF(activites.activity_type=2,1,0)) AS update_count,
SUM(IF(activites.activity_type=3,1,0)) AS print_count,
SUM(IF(activites.activity_type=4,1,0)) AS share_count,
IFNULL(COUNT(purchases.id),0) AS purchase_count
FROM
users
INNER JOIN activities ON activities.user_id=users.id
LEFT JOIN purchases ON purchases.user_id=users.id
GROUP BY users.id
I have the following query, in which I used JOINs. It says:
unknown column m.bv ..
Could you please take a look and tell me what I'm doing wrong?
$query4 = 'SELECT u.*, SUM(c.ts) AS total_sum1, SUM(m.bv) AS total_sum
FROM users u
LEFT JOIN
(SELECT user_id ,SUM(points) AS ts FROM coupon GROUP BY user_id) c
ON u.user_id=c.user_id
LEFT JOIN
(SELECT user_id ,SUM(points) AS bv FROM matching GROUP BY user_id) r
ON u.user_id=m.user_id
where u.user_id="'.$_SESSION['user_name'].'"
GROUP BY u.user_id';
You are selecting SUM(points) AS bv from the table with the alias r, there is no tables with the alias m. So that it has to be r.bv instead like so:
SELECT
u.*,
SUM(c.ts) AS total_sum1,
SUM(r.bv) AS total_sum
FROM users u
LEFT JOIN
(
SELECT
user_id,
SUM(points) AS ts
FROM coupon
GROUP BY user_id
) c ON u.user_id=c.user_id
LEFT JOIN
(
SELECT
user_id,
SUM(points) AS bv
FROM matching
GROUP BY user_id
) r ON u.user_id = m.user_id
where u.user_id="'.$_SESSION['user_name'].'"
GROUP BY u.user_id
Replace m., with r. Look at second Join
You have aliased the derived table with r and you reference that table (twice) with m. Correct one or the other.
Since you group by user_id in the two subqueries and user_id is (I assume) the primary key of table user, you don't really need the final GROUP BY.
I would write it like this, if it was meant for all (many) users:
SELECT u.*, COALESCE(c.ts, 0) AS total_sum1, COALESCE(m.bv, 0) AS total_sum
FROM users u
LEFT JOIN
(SELECT user_id, SUM(points) AS ts FROM coupon GROUP BY user_id) c
ON u.user_id = c.user_id
LEFT JOIN
(SELECT user_id, SUM(points) AS bv FROM matching GROUP BY user_id) m
ON u.user_id = m.user_id
and like this in your (one user) case:
SELECT u.*, COALESCE(c.ts, 0) AS total_sum1, COALESCE(m.bv, 0) AS total_sum
FROM users u
LEFT JOIN
(SELECT SUM(points) AS ts FROM coupon
WHERE user_id = "'.$_SESSION['user_name'].'") c
ON TRUE
LEFT JOIN
(SELECT SUM(points) AS bv FROM matching
WHERE user_id = "'.$_SESSION['user_name'].'") m
ON TRUE
WHERE u.user_id = "'.$_SESSION['user_name'].'"
The last query can also be simplified to:
SELECT u.*,
COALESCE( (SELECT SUM(points) FROM coupon
WHERE user_id = u.user_id)
, 0) AS total_sum1,
COALESCE( (SELECT SUM(points) FROM matching
WHERE user_id = u.user_id)
, 0) AS total_sum
FROM users u
WHERE u.user_id = "'.$_SESSION['user_name'].'"